Scintillator panel and scintillator panel manufacturing method

ABSTRACT

An object of the present invention is to enable a scintillator panel of a type having a barrier rib to have sufficient mechanical strength and enhanced brightness. A scintillator panel including a substrate, a barrier rib formed on the substrate, and a scintillator layer having a phosphor and sectioned by the barrier rib, wherein the barrier rib contains one or more compounds (P) selected from the group consisting of polyimides, polyamides, polyamideimides, and polybenzoxazoles.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. National Phase application of PCT/JP2021/011637, filedMar. 22, 2021 which claims priority to Japanese Patent Application No.2020-059633, filed Mar. 30, 2020, the disclosures of each of theseapplications being incorporated herein by reference in their entiretiesfor all purposes.

FIELD OF THE INVENTION

The present invention relates to a scintillator panel and a method ofproducing a scintillator panel.

BACKGROUND OF THE INVENTION

Radiographic images captured using films have been widely usedheretofore in medical settings. However, radiographic images capturedusing films are analog image information. Accordingly, a digitalradiation detector such as a flat panel detector (hereinafter referredto as an “FPD”) has been developed in recent years. In an FPD, ascintillator panel is used to convert a radiation into visible light. Ascintillator panel contains a radiation phosphor. The radiation phosphoremits visible light in response to an applied radiation. The lightemitted is converted into an electric signal using a TFT (thin filmtransistor) or a CCD (charge-coupled device), and the radiologicalinformation is converted into digital image information. However, ascintillator panel has a problem in that light emitted from a radiationphosphor scatters in a layer (phosphor layer) containing a phosphor,thus decreasing the sharpness of an image obtained.

Accordingly, what is being proposed for the purpose of decreasing theinfluence of the scatter of the emitted light is a method of packing aphosphor in a space sectioned by barrier ribs. Proposed examples ofmaterials for barrier ribs include glasses (Patent Document 1) andresins (Patent Document 2). The scatter of light emitted from a phosphoris inhibited by a barrier rib, thus making it possible to obtain anX-ray image having high sharpness.

PATENT DOCUMENTS

-   Patent Document 1: Japanese Patent Laid-open Publication No.    2019-168348-   Patent Document 2: Japanese Patent Laid-open Publication No.    2004-340737-   Patent Document 3: Japanese Patent Laid-open Publication No.    2019-190870

Non-Patent Document

-   Non-Patent Document 1: Daniel, J. H.; Fabrication of high    aspect-ratio polymer microstructures for large-area electronic    portal X-ray imagers [published online]; ELSEVIER; Jun. 28, 2007; p.    185-193.

SUMMARY OF THE INVENTION

In these methods, however, the amount of the phosphor is smaller by thevolume of the barrier ribs than a scintillator panel having no barrierrib. In addition, the barrier rib absorbs part of the light. Thesethings cause a problem in that the amount of light emitted by thephosphor is decreased, and the brightness of an X-ray image is decreasedthough the sharpness of the image is increased.

In addition, a scintillator panel described in Non-Patent Document 1,having barrier ribs produced using an epoxy resin, has a problem in thatthe mechanical strength is insufficient, and that the barrier rib isfractured and broken in the production processes of the scintillatorpanel.

In view of this, the present invention has been made, taking suchconventional problems into account. An object of the present inventionis to enable a scintillator panel of a barrier-rib-containing type tohave sufficient mechanical strength and enhanced brightness.

That is, the present invention according to exemplary embodiments is ascintillator panel including a substrate, a barrier rib formed on thesubstrate, and a scintillator layer having a phosphor and sectioned bythe barrier rib, wherein the barrier rib contains one or more compounds(P) selected from the group consisting of polyimides, polyamides,polyamideimides, and polybenzoxazoles.

In addition, the present invention according to exemplary embodiments isa method of producing a scintillator panel, including: a barrier ribforming step of forming a barrier rib on a substrate to define cells; areflecting layer forming step of forming a metal reflecting layer on thesurface of the barrier rib; a packing step of packing a phosphor in thecells defined by the barrier rib; wherein the barrier rib contains oneor more compounds (P) selected from the group consisting of polyimides,polyamides, polyamideimides, and polybenzoxazoles and a structurederived from an epoxy compound.

The present invention makes it possible that a scintillator panel of abarrier-rib-containing type has a barrier rib having sufficientmechanical strength, and also exhibits enhanced brightness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view depicting a member for aradiation detector including a scintillator panel according to anembodiment of the present invention.

FIG. 2 is a schematic cross-sectional view depicting a scintillatorpanel according to an embodiment of the present invention.

FIG. 3 is a schematic top view of one example of a scintillator panelaccording to an embodiment of the present invention.

DETAILED DESCRIPTION EMBODIMENTS OF THE INVENTION

(Scintillator Panel)

Below, embodiments of a scintillator panel according to the presentinvention will be described with reference to the drawings. In thisregard, the drawings are schematic. In addition, the present inventionis not to be limited to the embodiments described below.

FIG. 1 is a schematic cross-sectional view depicting a member 1 for aradiation detector including a scintillator panel 2 according to anembodiment of the present invention. The member 1 for a radiationdetector has the scintillator panel 2 and an output substrate 3. Thescintillator panel 2 has a substrate 4, a barrier rib 5, and a phosphorlayer 6 in a cell defined by the barrier rib 5. The barrier rib 5 has ametal reflecting layer (hereinafter referred to as a “first reflectinglayer”) 11 formed on the surface thereof, and the metal reflecting layerhas a protective layer 12 provided on the surface thereof. Furthermore,the protective layer 12 has a second reflecting layer 13 provided on thesurface thereof. The phosphor layer 6 contains a phosphor 14 and abinder resin 15. The output substrate 3 has a substrate 10, an outputlayer 9 formed on the substrate 10, and a photoelectric conversion layer8 having a photodiode and formed on the output layer 9. A barriermembrane layer 7 may be provided on the photoelectric conversion layer8. It is preferable that the light exit face of the scintillator panel 2and the photoelectric conversion layer 8 of the output substrate 3 arebonded or adhere to each other with the barrier membrane layer 7interposed therebetween. The light emitted from the phosphor layer 6reaches the photoelectric conversion layer 8 to be photoelectricallyconverted and outputted. Below, each of the parts will be described.

(Substrate)

The material constituting the substrate 4 is preferably a radiolucentmaterial. The material constituting the substrate 4 is, for example, anykind of glass, polymer material, metal, or the like. Examples of glassesinclude quartz, borosilicate glass, chemically tempered glasses, and thelike. Examples of polymer materials include: cellulose acetate;polyesters such as polyethylene terephthalate and polyethylenenaphthalate; polyamides; polyimides; triacetate; polycarbonates; carbonfiber reinforced resins; and the like. Examples of metals includealuminum, iron, copper, and the like. Two or more of these may be usedin combination. The material constituting the substrate 4 is preferablyglass or a polymer material among these from the viewpoints ofradiolucency and surface smoothness, and is more preferably a polymermaterial. Among the polymer materials, polyesters such as polyethyleneterephthalate and polyethylene naphthalate, polyamides, and polyimidesare preferable.

From the viewpoint of making the scintillator panel 2 more lightweight,the substrate 4 preferably has a thickness of 2.0 mm or less, morepreferably 1.0 mm or less, in cases where the substrate is a glasssubstrate. Alternatively, the substrate 4 preferably has a thickness of3.0 mm or less in cases where the substrate is composed of a polymermaterial.

(Barrier Rib)

The barrier rib 5 is provided at least to form defined spaces (cells).Accordingly, with the scintillator panel 2, making it possible that thesize and pitch of a pixel of a photoelectric conversion element arrangedin grid-like form are identical with the size and pitch of a cell of thescintillator panel 2 makes it possible that each pixel of thephotoelectric conversion element corresponds to each cell of thescintillator panel 2. This makes it possible that the scintillator panel2 is used to obtain an image having high sharpness.

The barrier rib 5 contains one or more compounds (P) (hereinafterreferred to simply as the “compound (P)”) selected from the groupconsisting of polyimides, polyamides, polyamideimides, andpolybenzoxazoles. A scintillator panel according to an embodiment of thepresent invention includes the barrier rib containing the compound (P),thereby making it possible to enhance the brightness. The principle ofthis is considered to consist mainly in the below-mentioned two points.However, the below-mentioned inferable principle is not limitative. Inaddition, both of the below-mentioned two points do not always have tobe satisfied together.

The barrier rib containing the compound (P) can be formed in the shapeof a pattern that is fine and has a high aspect ratio, compared with thebarrier rib composed of glass or the like. Accordingly, increasing theamount of the phosphor packed in the scintillator layer makes itpossible to enhance the brightness.

In addition, the barrier rib having the compound (P) has excellentsurface smoothness. This is presumably because the compound (P) hasexcellent heat resistance, mechanical characteristics, and chemicalresistance, and thus, is less susceptible to chemical and mechanicaldamage from the outside in the below-mentioned step of producing thebarrier rib and other production steps for the scintillator panel, sothat the deformation, fracture, or breakage of the barrier rib is lesslikely to follow. In addition, the barrier rib having excellent surfacesmoothness makes it possible to increase the reflectance of light at thesurface of the barrier rib. Additionally, in cases where a reflectinglayer is formed on the surface of such a barrier rib, the barrier ribmakes it possible to form a reflecting layer having high smoothness.This makes it possible to enhance the takeout efficiency of lightemitted from the phosphor, and enhance the brightness.

The compound (P) is preferably a polyimide from the viewpoints of heatresistance, chemical resistance, and mechanical strength.

The surface smoothness of the barrier rib can be evaluated using anexisting surface roughness measurement method. Examples of surfaceroughness measurement methods include methods of a stylus type, lightinterference type, or laser microscope type. To evaluate the surfaceroughness of a structure intricate as the side of the barrier rib, amethod based on using a laser microscope is preferably used. Anevaluation index to be used preferably for surface roughness is anarithmetic average slope angle determined by arithmetically averaging aslope (slope angle) made by each minute portion of a curve given bymeasuring the surface shape. The smaller the value of the arithmeticaverage slope angle, the smoother the surface shape.

In cases where a photosensitive resin composition is produced using thecompound (P), the photosensitive material is limited to no particularcomponent. Examples of the composition include: photo-radicalpolymerizable negative-type photosensitive resin compositions given byadding a polyfunctional acryl monomer and a photo-radical polymerizationinitiator to the compound (P); photo-cationic polymerizationnegative-type photosensitive resin compositions given by adding an epoxycompound and a photo-cationic polymerization initiator to the compound(P); photosoluble positive-type photosensitive resin compositions givenby adding a naphthoquinone photosensitizer to the compound (P); and thelike. In particular, among these, a photo-cationic polymerizablenegative-type photosensitive resin composition containing an epoxycompound can form a barrier rib having a high aspect ratio, and hence,is preferable.

The compound (P) is preferably a compound having at least one repeatingunit structure selected from the structures represented by the followinggeneral formulae (1) to (2).

In the general formulae (1) to (2), X¹ represents a di- to octa-valentorganic group, X² represents a tetra- to octa-valent organic group, Y¹and Y² independently represent a di- to hexa-valent organic group, andR¹ represents a hydrogen atom or a C₁-C₂₀ hydrocarbon group. q is aninteger of 0 to 2, and r, s, t, and u are independently an integer of 0to 4.

Y¹ and Y² represent an organic group derived from a diamine. Y¹ and Y²preferably contain a hydrocarbon group, more preferably contains anaromatic hydrocarbon group or an alicyclic hydrocarbon group. Containingan aromatic hydrocarbon group or an alicyclic hydrocarbon group makes itpossible to further enhance the heat resistance of the resin, thusmaking it possible to maintain the shape and smoothness of the barrierrib in the below-mentioned step of producing a scintillator panel. Thecarbon number of a hydrocarbon group contained in Y¹ and Y² ispreferably 5 to 40.

Y¹ and Y² are preferably a diamine residue having a structure derivedfrom a phenolic hydroxyl group. A photosensitive resin composition thatcontains a diamine residue having a structure derived from a phenolichydroxyl group, that is, contains the compound (P) contains a diamineresidue having a phenolic hydroxyl group, and thus enables the resin tohave suitable solubility in an alkaline developer, hence making itpossible to obtain high contrast between the exposed portion and theunexposed portion, and form a desired pattern. A structure derived froma phenolic hydroxyl group specifically means an ether bond or a urethanebond that contain an aromatic ring, and is formed by allowing a phenolichydroxyl group to react with a cyclic ether compound such as epoxy oroxetane, an isocyanate compound, or the like.

Specific examples of diamines having a phenolic hydroxyl group include,but are not limited to; aromatic diamines such asbis(3-amino-4-hydroxyphenyl)hexafluoropropane,bis(3-amino-4-hydroxyphenyl)sulfone,bis(3-amino-4-hydroxyphenyl)propane,bis(3-amino-4-hydroxyphenyl)methylene,bis(3-amino-4-hydroxyphenyl)ether, bis(3-amino-4-hydroxy)biphenyl,2,2′-ditrifluoromethyl-5,5′-dihydroxyl-4,4′-diaminobiphenyl,bis(3-amino-4-hydroxyphenyl)fluorene, and2,2′-bis(trifluoromethyl)-5,5′-dihydroxybenzidine; the same compounds asthese except that part of the hydrogen atoms of the aromatic ring or thehydrocarbon is/are substituted with a C₁-C₁₀ alkyl group, fluoroalkylgroup, halogen atom, or the like; diamines having a structurerepresented as below-mentioned; and the like. In addition, these diaminecomponents may be contained in combination of two or more kinds thereof.

The compound (P) may contain an aromatic diamine residue other thanthese. Specific examples of aromatic diamines include, but are notlimited to: aromatic diamines such as 3,4′-diaminodiphenyl ether,4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenylmethane,4,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylsulfone,4,4′-diaminodiphenylsulfone, 3,4′-diaminodiphenyl sulfide,4,4′-diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, benzine,m-phenylene diamine, p-phenylene diamine, 1,5-naphthalene diamine,2,6-naphthalene diamine, bis(4-aminophenoxyphenyl)sulfone,bis(3-aminophenoxyphenyl)sulfone, bis(4-aminophenoxy)biphenyl,bis{4-(4-aminophenoxy)phenyl} ether, 1,4-bis(4-aminophenoxy)benzene,2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl,3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl,2,2′,3,3′-tetramethyl-4,4′-diaminobiphenyl,3,3′,4,4′-tetramethyl-4,4′-diaminobiphenyl; and2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl; the same compounds asthese except that part of the hydrogen atoms of the aromatic ring or thehydrocarbon is/are substituted with a C₁-C₁₀ alkyl group, fluoroalkylgroup, halogen atom, or the like; and the like. In addition, thesediamine components may be contained or used in combination of two ormore kinds thereof.

X¹ and X² represent a carboxylic residue. X¹ and X² preferably contain ahydrocarbon group, more preferably contains an aromatic hydrocarbongroup or an alicyclic hydrocarbon group. Containing an aromatichydrocarbon group or an alicyclic hydrocarbon group makes it possible tofurther enhance the heat resistance of the resin, thus making itpossible to maintain the shape and smoothness of the barrier rib in thebelow-mentioned step of producing a scintillator panel.

Furthermore, it is more preferable to contain an alicyclic hydrocarbongroup in that the color of the resin is transparent with respect to awavelength to be used during the below-mentioned formation of a barrierrib, and that the barrier rib can be processed in the form of a thickand fine pattern.

The carbon number of a hydrocarbon group contained in X¹ and X² ispreferably 5 to 40. Examples of more preferable carboxylic acidscontaining a hydrocarbon group include carboxylic acids that containcarbon and hydrogen as essential atoms, and may have one or more atomsselected from the group consisting of nitrogen, oxygen, and halogen.

Specific examples of carboxylic acids containing a hydrocarbon groupinclude, but are not limited to: terephthalic acid; isophthalic acid;diphenyl ether dicarboxylate; bis(carboxy phenyl)hexafluoropropane;biphenyl dicarboxylate; benzophenone dicarboxylate; triphenyldicarboxylate;5-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]-1,3-benzenedicarboxylate; trimellitic acid; trimesic acid; diphenyl ethertricarboxylic acid; biphenyltricarboxylic acid; pyromellitic acid;3,3′,4,4′-biphenyltetracarboxylic acid;2,3,3′,4′-biphenyltetracarboxylic acid;2,2′,3,3′-biphenyltetracarboxylic acid;3,3′,4,4′-benzophenonetetracarboxylic acid;2,2′,3,3′-benzophenonetetracarboxylic acid;1,1-bis(3,4-dicarboxyphenyl)ethane; 1,1-bis(2,3-dicarboxyphenyl)ethane;bis(3,4-dicarboxyphenyl)methane; bis(2,3-dicarboxyphenyl)methane;bis(3,4-dicarboxyphenyl)ether; 1,2,5,6-naphthalenetetracarboxylic acid;2,3,6,7-naphthalenetetracarboxylic acid; 2,3,5,6-pyridinetetracarboxylicacid; 3,4,9,10-perylenetetracarboxylic acid;4,4′-(hexafluoroisopropylidene)diphthalic acid;1,2,3,6-tetrahydrophthalic anhydride; ethylene glycolbisanhydrotrimellitate; 1,2,3,4-butanetetracarboxylic dianhydride;1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-C]furan-1,3-dione;and 5-norbornene-2,3-dicarboxylic anhydride; aromatic tetracarboxylicacids having the below-mentioned structure; aliphatic tetracarboxylicacids such as butanetetracarboxylic acid and1,2,3,4-cyclopentanetetracarboxylic acid; and the like.

In addition, these carboxylic acid components may be contained or usedin combination of two or more kinds thereof.

In the general formula (1) above, R¹ represents a hydrogen atom or aC₁-C₂₀ hydrocarbon group. Examples of hydrocarbon groups includealiphatic hydrocarbon groups and aromatic hydrocarbon groups. Such analiphatic hydrocarbon group may be linear or branched, and may bepartially or wholly cyclic. In the aromatic hydrocarbon group, at leastone of the hydrogen atoms may be substituted with an aliphatichydrocarbon.

The molar ratio of a structure represented by the general formulae (1)and (2) can be verified by a method of calculating the molar ratio of amonomer used for polymerization, or a method of using a nuclear magneticresonance device (NMR) to detect a peak from a polyamide structure,imide precursor structure, imide structure, or oxazole structure in theresulting resin, resin composition, or cured film.

An end of the molecular chain of the compound (P) is preferably acarboxylic residue. Having a structure in which an end of the molecularchain of the compound (P) is derived from a carboxylic residuefacilitates the progress of cationic polymerization and the formation ofa barrier rib having a desired shape, compared with having a structurein which an end of the molecular chain is derived from a diamineresidue, even in cases where the resulting product is a photo-cationicpolymerizable resin composition containing the compound (P). As aresult, it is possible to increase the packing amount of the phosphorand to enhance the brightness. Such a compound (P) can be obtained bymaking the amount of an acid anhydride larger than that of a diamineused for polymerization. Another method of obtaining the compound (P)containing a carboxylic residue as an end of the molecular chain is amethod in which the compound can be obtained by using a specificcompound, specifically, an acid anhydride, monocarboxylic acid, monoacidchloride compound, monoactive ester compound from among compounds to beused commonly as end-capping agents.

In addition, capping an end of the molecular chain of the compound (P)with an end-capping agent of a carboxylic acid or an acid anhydridehaving a hydroxyl group, carboxyl group, sulfonic group, thiol group,vinyl group, ethynyl group, or allyl group makes it possible to easilyadjust the dissolution rate of the compound (P) to an aqueous alkalisolution and the mechanical characteristics of the resulting cured filmwithin a preferable range. In addition, it is possible to allow aplurality of end-capping agents to react, thus introducing a pluralityof different end groups.

Preferable examples of acid anhydrides, monocarboxylic acids, monoacidchloride compounds, and monoactive ester compounds as end-capping agentsinclude: acid anhydrides such as phthalic anhydride, maleic anhydride,nadic anhydride, cyclohexanedicarboxylic anhydride, and3-hydroxyphthalic anhydride; monocarboxylic acids such as3-carboxyphenol, 4-carboxyphenol, 3-carboxythiophenol,4-carboxythiophenol, 1-hydroxy-7-carboxynaphthalene,1-hydroxy-6-carboxynaphthalene, 1-hydroxy-5-carboxynaphthalene,1-mercapto-7-carboxynaphthalene, 1-mercapto-6-carboxynaphthalene,1-mercapto-5-carboxynaphthalene, 3-carboxybenzenesulfonic acid, and4-carboxybenzenesulfonic acid, and monoacid chloride compounds obtainedby forming a carboxyl group of such a monocarboxylic acid into an acidchloride; monoacid chloride compounds obtained by forming, into an acidchloride, only one of the carboxyl groups of a dicarboxylic acid such asterephthalic acid, phthalic acid, maleic acid, cyclohexanedicarboxylicacid, 1,5-dicarboxynaphthalene, 1,6-dicarboxynaphthalene,1,7-dicarboxynaphthalene, or 2,6-dicarboxynaphthalene; active estercompounds obtained by allowing a monoacid chloride compound to reactwith N-hydroxybenzotriazole, imidazole, orN-hydroxy-5-norbornene-2,3-dicarboxyimide; and the like. These may beused in combination of two or more kinds thereof.

The compound (P) having such an end-capping agent introduced thereinbecomes a compound containing a carboxylic residue as an end of themolecular chain. An end-capping agent that can be used to obtain thecompound (P) containing a carboxylic residue as an end of the molecularchain can be detected easily by the below-mentioned method. For example,an end-capping agent used in the present invention can be detectedeasily as follows: a compound (P) having an end-capping agent introducedtherein is dissolved in an acidic solution, and decomposed into an aminecomponent and an acid anhydride component that are the constituentunits, and the components are detected by gas chromatography (GC) orNMR. Besides this, using a pyrolysis gas chromatograph (PGC), infraredspectrum, and ¹³C-NMR spectrum to directly measure a resin componenthaving an end-capping agent introduced therein enables easy detection.

The compound (P), for example, a polyimide or a polybenzoxazole issynthesized by the following method, but the synthesis method is notlimited thereto. A polyimide structure is synthesized by a known methodin which part of a diamine is replaced with a primary monoamine as anend-capping agent, or in which a tetracarboxylic dianhydride is replacedwith a dicarboxylic anhydride as an end-capping agent. For example, apolyimide precursor is obtained by utilizing a method such as: a methodin which a tetracarboxylic dianhydride, diamine compound, and monoamineare allowed to react at low temperature; a method in which atetracarboxylic dianhydride, dicarboxylic anhydride, and diaminecompound are allowed to react at low temperature; or a method in which adiester is obtained from a tetracarboxylic dianhydride and an alcohol,and allowed to react in the presence of a diamine, monoamine, andcondensing agent. Then, a polyimide can be synthesized by utilizing aknown imidization reaction method.

A polybenzoxazole structure is synthesized by a condensation reactionbetween a bisaminophenol compound and a dicarboxylic acid. For example,a polybenzoxazole precursor is obtained by utilizing the followingmethod: a method in which a dehydrating condensing agent such asdicyclohexylcarbodiimide (DCC) and an acid are allowed to react, and tothe resulting product, a bisaminophenol compound is added; a method inwhich a dicarboxylic dichloride solution is added dropwise to a solutionof a bisaminophenol compound supplemented with a tertiary amine such aspyridine; or the like. Then, a polybenzoxazole can be synthesized byutilizing a known condensation reaction method. It is preferable that,after being polymerized by the above-mentioned method, the compound (P)is added to a large amount of water, a liquid mixture of methanol andwater, or the like, precipitated, filtrated, and dried to be isolated.The drying temperature is preferably 40 to 100° C., more preferably 50to 80° C. This operation makes it possible to remove an unreactedmonomer and an oligomer component such as a dimer or a trimer, and toenhance the film characteristics obtained after heat-curing.

The imidization ratio of a polyimide or a polyamideimide can bedetermined easily, for example, by the below-mentioned method. First, aninfrared absorption spectrum of a polymer is measured to verify theoccurrence of absorption peaks (near 1780 cm⁻¹ and 1377 cm⁻¹) of animide structure that are attributable to a polyimide and apolyamideimide. Next, the polymer is heat-treated at 350° C. for 1 hour,and the resulting polymer is used as a sample having an imidizationratio of 100% to measure an infrared absorption spectrum. On the basisof the comparison between the resins before and after the heat-treatmentin terms of the peak intensity near 1377 cm⁻¹, the amount of the imidegroup in the resin before the heat-treatment is calculated to determinethe imidization ratio. The imidization ratio is preferably 50% or more,still more preferably 80% or more, because of inhibiting a change in thering closure ratio during heat-curing, and obtaining the effect oflowering the stress.

(Epoxy Compound)

It is preferable that the barrier rib 5 further contains a structurederived from an epoxy compound, that is, that the photosensitive resincomposition contains a compound (P) containing an epoxy compound. Anepoxy compound makes it possible to further enhance the processabilitywithout impairing the heat resistance and mechanical strength of thecompound (P), and thus, makes it easier to form the below-mentionedbarrier rib having a desired shape. This makes it possible to increasethe packing amount of the phosphor and to enhance the brightness. Astructure derived from an epoxy compound specifically means an acyclicether bond or a hydroxyl group generated by the ring-opening of anepoxy, and is formed by the polymerization of an epoxy compound, theaddition reaction or the like of a phenolic hydroxyl group, or the like.

The amount of an epoxy compound contained in the photosensitive resincomposition preferably does not exceed 2.0 times the amount of thecompound (P) in terms of the mass fraction in order not to impair thecharacteristics of the compound (P). In cases where the photosensitiveresin composition contains a component other than the compound (P) andan epoxy compound, the total amount of the component is preferably notmore than the total amount of the compound (P) and an epoxy compound interms of the mass fraction.

An epoxy compound that can be used is any known epoxy compound or thelike. Examples thereof include aromatic epoxy compounds, alicyclic epoxycompounds, and aliphatic epoxy compounds.

Examples of aromatic epoxy compounds include: a glycidyl ether of amonovalent or multivalent phenol (a phenol, bisphenol A, phenol novolac,or alkylene oxide adduct compound thereof) having at least one aromaticring; and the like.

Examples of alicyclic epoxy compounds include a compound(3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate or the like)obtained by epoxidizing, with an oxidizing agent, a compound having atleast one cyclohexene or cyclopentene ring.

Examples of aliphatic epoxy compounds include: a polyglycidyl ether ofan aliphatic multivalent alcohol or an alkylene oxide adduct thereof(1,4-butanedioldiglycidyl ether, 1,6-hexanedioldiglycidyl ether, or thelike); a polyglycidyl ester of an aliphatic polybasic acid (diglycidyltetrahydrophthalate or the like); an epoxidized product of a long-chainunsaturated compound (an epoxidized soybean oil, an epoxidizedpolybutadiene, or the like).

Epoxy compounds containing a nitrogen atom are preferable from theviewpoints of enhancing the compatibility with a polyimide, obtainingfine pattern processability, and in addition, not decreasing the goodheat resistance and mechanical characteristics of a polyimide.Furthermore, an epoxy compound containing an isocyanurate backbone ispreferable from the viewpoint of enhancing the storage stability of theresulting resin composition.

Examples of epoxy compounds containing an isocyanurate backbone include:TEPIC-S, TEPIC-L, TEPIC-VL, TEPIC-PASB22, and TEPIC-FL (tradenames, allmanufactured by Nissan Chemical Corporation) that are triglycidylisocyanurates; and the like.

Aliphatic epoxy compounds are preferable from the viewpoint of notdecreasing the transparency of the resin composition and the goodmechanical characteristics of a polyimide. Examples of aliphatic epoxycompounds include: SHOFREE BATG and SHOFREE PETG (tradenames, allmanufactured by Showa Denko K.K.); DENACOL EX-321L and DENACOL EX-521(tradenames, all manufactured by Nagase ChemteX Corporation); and thelike.

Alicyclic epoxy compounds are preferable from the viewpoint ofreactivity at low temperature. Examples of alicyclic epoxy compoundsinclude: CELLOXIDE 2000, CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE8081, and EPOLEAD GT401 (tradenames, all manufactured by DaicelCorporation); and the like.

These epoxy compounds may be used singly or in combination of two ormore kinds thereof.

The epoxy compound is preferably cured by cationic polymerization.Curing the epoxy by cationic polymerization makes it less likely tocause insufficient curing due to oxygen inhibition during processing,and makes it easier to form the below-mentioned barrier rib having adesired shape.

The amount of an epoxy compound contained in the photosensitive resincomposition is preferably 30 parts by mass or more, more preferably 50parts by mass or more, with respect to 100 parts by mass of the compound(P), from the viewpoints of exhibiting sufficient cationic curability,and enhancing the pattern processability. On the other hand, the amountis preferably 200 parts by mass or less, more preferably 100 parts bymass or less, from the viewpoint of not decreasing the characteristicsof the compound (P).

In addition, the amount of a structure derived from an epoxy compoundpreferably corresponds to 3 mol or more and 25 mol or less when theamount of the compound (P) in the barrier rib is 1 mol. A method thatcan be used to calculate the amount of an epoxy compound with respect tothe compound (P) in the barrier rib is any known such method. Forexample, a nuclear magnetic resonance device (NMR) can be used forverification in a method of calculation from an integral value of a peakof a structure derived from the compound (P) and a peak of a structurederived from an epoxy compound in the barrier rib.

(Another Component)

A photo-cationic polymerization initiator contained in thephoto-cationic polymerizable negative-type photosensitive resincomposition generates acid directly or indirectly by virtue of light tocause cationic polymerization. Any known such compound can be usedwithout any particular limitation. Specific examples include aromaticiodonium complex salts, aromatic sulfonium complex salts, and the like.Specific examples of aromatic iodonium complex salts includediphenyliodoniumtetrakis(pentafluorophenyl)borate,diphenyliodoniumhexafluorophosphate,diphenyliodoniumhexafluoroantimonate,di(4-nonylphenyl)iodoniumhexafluorophosphate, and the like. Thesephoto-cationic polymerization initiators may be used singly or incombination of two or more kinds thereof.

The amount of the photo-cationic polymerization initiator is preferably0.3 parts by mass or more, more preferably 0.5 parts by mass or more,with respect to 100 parts by mass of the epoxy compound. This enablesthe epoxy compound to exhibit sufficient curability, and makes itpossible to enhance the pattern processability. On the other hand, theamount is preferably 18 parts by weight or less, more preferably 15parts by weight or less, from the viewpoint of enhancing the storagestability of the photosensitive resin composition.

For a photo-cationic polymerizable negative-type photosensitive resincomposition, a sensitizer may be used to absorb ultraviolet rays andprovide a photo-acid generator with the light energy absorbed. Examplesof preferable sensitizers include anthracene compounds having an alkoxygroup at the 9-position and the 10-position (9,10-dialkoxy-anthracenederivative). Examples of alkoxy groups include C₁-C₄ alkoxy groups suchas a methoxy group, ethoxy group, and propoxy group. The9,10-dialkoxy-anthracene derivative may further have a substituent.Examples of substituents include: halogen atoms such as a fluorine atom,chlorine atom, bromine atom, and iodine atom; C₁-C₄ alkyl groups such asa methyl group, ethyl group, and propyl group; a sulfonic acid alkylester group; a carboxylic acid alkyl ester group; and the like. Examplesof alkyls in sulfonic acid alkyl ester groups and carboxylic acid alkylesters include C₁-C₄ alkyls such as methyl, ethyl, and propyl. Thesubstitution position of such a substituent is preferably the2-position.

The photo-cationic polymerizable negative-type photosensitive resincomposition may contain a thermal cross-linking agent, preferably acompound having an alkoxy methyl group or a methylol group.

Examples of compounds having an alkoxy methyl group or a methylol groupinclude: DML-PC, DML-PEP, DML-OC, DML-OEP, DML-34X, DML-PTBP, DML-PCHP,DML-OCHP, DML-PFP, DML-PSBP, DML-POP, DML-MBOC, DML-MBPC, DML-MTrisPC,DML-BisOC-Z, DML-BisOCHP-Z, DML-BPC, DML-BisOC-P, DMOM-PC, DMOM-PTBP,DMOM-MBPC, TriML-P, TriML-35XL, TML-HQ, TML-BP, TML-pp-BPF, TML-BPE,TML-BPA, TML-BPAF, TML-BPAP, TMOM-BP, TMOM-BPE, TMOM-BPA, TMOM-BPAF,TMOM-BPAP, HML-TPPHBA, HML-TPHAP, HMOM-TPPHBA, and HMOM-TPHAP(tradenames, all manufactured by Honshu Chemical Industry Co., Ltd.);and NIKALAC (registered trademark) MX-290, NIKALAC MX-280, NIKALACMW-100LM, and NIKALAC MX-750LM (tradenames, all manufactured by SanwaChemical Co., Ltd.).

The photo-cationic polymerizable negative-type photosensitive resincomposition can further contain a silane compound. Containing a silanecompound makes it possible to enhance the adhesiveness of theheat-resistant resin coating. Specific examples of silane compoundsinclude N-phenylaminoethyltrimethoxy silane, N-phenylaminoethyltriethoxysilane, N-phenylaminopropyltrimethoxy silane,N-phenylaminopropyltriethoxy silane, N-phenylaminobutyltrimethoxysilane, N-phenylaminobutyltriethoxy silane, vinyltrimethoxy silane,vinyltriethoxy silane, vinyltrichlor silane,vinyltris(β-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxy silane,3-acryloxypropyltrimethoxy silane, p-styryltrimethoxy silane,3-methacryloxypropylmethyldimethoxy silane,3-methacryloxypropylmethyldiethoxy silane, and the like.

As required, for the purpose of enhancing the wettability with a basematerial, the photo-cationic polymerizable negative-type photosensitiveresin composition may contain the following: a surfactant; an ester suchas ethyl lactate or propylene glycol monomethyl ether acetate; analcohol such as ethanol; a ketone such as cyclohexanone ormethylisobutyl ketone; and/or an ether such as tetrahydrofuran ordioxane. It is also possible to contain inorganic particles such as ofsilicon dioxide or titanium dioxide, powder of polyimide, or the likefor the purposes of restricting the thermal expansion coefficient,increasing the permittivity, decreasing the permittivity, or the like.

The photosensitive resin composition is preferably used in the form of asolution (varnish) containing an organic solvent. Specific examples oforganic solvents include: ethers such as ethylene glycol monomethylether, ethylene glycol monoethyl ether, propylene glycol monomethylether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether,ethylene glycol diethyl ether, and ethylene glycol dibutyl ether;acetates such as ethylene glycol monoethyl ether acetate, propyleneglycol monomethyl ether acetate, propyl acetate, butyl acetate, isobutylacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyllactate, ethyl lactate, butyl lactate, and ethyl acetoacetate; ketonessuch as acetone, methylethyl ketone, acetylacetone, methylpropyl ketone,methylbutyl ketone, methylisobutyl ketone, cyclopentanone, and2-heptanone; alcohols such as butyl alcohol, isobutyl alcohol, pentanol,4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxy butanol, anddiacetone alcohol; aromatic hydrocarbons such as toluene and xylene;others such as N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone,N,N-dimethylformamide, N,N-dimethyl acetamide, dimethyl sulfoxide, andγ-butyrolactone; and the like.

In addition, the varnish of the photosensitive resin composition may befiltrated using a paper filter or a filter before being applied. Thefiltration method is subject to no particular limitation, and ispreferably a filtration performed under pressure using a filter for aretention particle diameter of 0.4 μm to 10 μm.

The viscosity of the varnish of the photosensitive resin composition canbe adjusted suitably in accordance with the molecular weight of thecompound (P) and the concentration of the solution, and is preferably2000 mPa·s or more, more preferably 5000 mPa·s or more. In addition, theviscosity is preferably 200000 mPa·s or less, more preferably 100000mPa·s or less. For example, in cases where the varnish is applied to abase material using a spin coating method, the viscosity is preferably2000 to 5000 mPa·s. In cases where the varnish is applied to a basematerial using a blade coater method or a die coater method, theviscosity is preferably 10000 to 50000 mPa·s.

(Shape of Barrier Rib)

FIG. 2 is a schematic cross-sectional view depicting an extract of thescintillator panel 2 portion in FIG. 1 . However, the first reflectinglayer 11 is omitted for the ease of understanding of the followingdescription. The height L1 of the barrier rib 5 is preferably 50 μm ormore, more preferably 70 μm or more. In addition, the height of thebarrier rib 5 is preferably 3000 μm or less, more preferably 1000 μm orless. With L1 at 3000 μm or less, light emitted by the phosphor 14itself is less easily absorbed, and the brightness of the scintillatorpanel 2 is further enhanced. On the other hand, with L1 at 50 μm ormore, the scintillator panel 2 allows the phosphor 14 to be packed in asuitable amount therein, and exhibits further enhanced brightness.

The distance L2 between the adjacent barrier ribs 5 is preferably 30 μmor more, more preferably 40 μm or more. In addition, the distance L2between the adjacent barrier ribs 5 is preferably 3000 μm or less, morepreferably 2000 μm or less. With L2 at 30 μm or more, the phosphor 13can be packed more easily in the cells of the scintillator panel 2. Onthe other hand, with L2 at 3000 μm or less, the scintillator panel 2 canproduce an image having better sharpness.

The bottom width L3 of the barrier rib 5 is preferably 2 μm or more,more preferably 3 μm or more. In addition, the bottom width L3 ispreferably 150 μm or less, more preferably 80 μm or less, still morepreferably 50 μm or less. With L3 at 2 μm or more, the scintillatorpanel 2 is less prone to have a defect in the pattern. On the otherhand, with L3 at 150 μm or less, the scintillator panel 2 allows thephosphor 13 to be packed in a suitable amount therein, and is less proneto cause a decrease in the brightness.

The top width L4 of the barrier rib 5 is preferably 2 μm or more, morepreferably 3 μm or more. In addition, the top width L4 is preferably 80μm or less, more preferably 50 μm or less, still more preferably 20 μmor less. With L4 at 2 μm or more, the strength of the barrier rib 5 issuitable, and the scintillator panel 2 is less prone to have a defect inthe pattern. On the other hand, with L4 at 80 μm or less, thescintillator panel 2 has a suitable region over which light emitted bythe phosphor 14 can be taken out. Thus, the brightness is furtherenhanced.

An aspect ratio (L1/L3) of the height L1 of the barrier rib 5 to thebottom width L3 of the barrier rib 5 is preferably 5.0 or more, morepreferably 10.0 or more, still more preferably 12.0 or more. Inaddition, the aspect ratio (L1/L3) is preferably 100.0 or less, morepreferably 50.0 or less. With the aspect ratio (L1/L3) at 5.0 or more,the scintillator panel 2 allows the phosphor 14 to be packed in asuitable amount therein, and is less prone to cause a decrease in theX-ray absorption efficiency. In addition, with the aspect ratio (L1/L3)at 100.0 or less, the strength of the barrier rib in the scintillatorpanel 2 is more likely to be suitable.

An aspect ratio (L1/L2) of the height L1 of the barrier rib 5 to thedistance L2 between the barrier ribs 5 is preferably 0.5 or more, morepreferably 1.0 or more. In addition, the aspect ratio (L1/L2) ispreferably 20.0 or less, more preferably 10.0 or less. With the aspectratio (L1/L2) at 0.5 or more, the scintillator panel 2 is less prone tocause a decrease in the X-ray absorption efficiency. In addition, withthe aspect ratio (L1/L2) at 20.0 or less, the scintillator panel 2 isless prone to cause a decrease in the takeout efficiency of light, andexhibits further enhanced brightness. However, as illustrated FIG. 3 ,the above description may be inapplicable in cases where the distance L2between the barrier ribs 5 is different between the length (L2(X)) inthe X-axis direction and the length (L2(Y)) in the Y-axis direction. Incases where the X-axis direction and the Y-axis direction are set as perL2(X)>L2(Y), the aspect ratio (L1/L2(X)) of the height L1 of the barrierrib 5 is preferably 0.05 or more, more preferably 0.2 or more. Inaddition, the aspect ratio (L1/L2(X)) is preferably 10.0 or less, morepreferably 5.0 or less.

A ratio (L4/L3) of the top width L4 to the bottom width L3 of thebarrier rib 5 is preferably 0.5 or more, more preferably 0.7 or more.Having the ratio at 0.5 or more makes it possible to maintain theintensity of the barrier rib, and at the same time, to increase theamount of the phosphor.

The height L1 of the barrier rib 5 and the distance L2 between theadjacent barrier ribs 5 can be measured by cutting out a cross sectionperpendicular to a substrate or baring a cross section using a polishingdevice such as a cross-section polisher, and then observing the crosssection under a scanning electron microscope. Here, the width of thebarrier rib 5 across the contact portion between the barrier rib 5 andthe substrate is denominated L3. In addition, the width of the topportion of the barrier rib 5 is denominated L4.

(First Reflecting Layer)

In a scintillator panel according to an embodiment of the presentinvention, the barrier rib 5 preferably has a metal-containingreflecting layer (first reflecting layer) 11 on the surface thereof. Thefirst reflecting layer 11 is preferably provided on at least a part ofthe barrier rib 5. Even if a thin film, the first reflecting layer 11has a high reflectance. Accordingly, having the first reflecting layer11 that is a thin film makes it less likely to decrease the packingamount of the phosphor 13, and the scintillator panel 2 exhibits furtherenhanced brightness.

The metal constituting the first reflecting layer 11 is subject to noparticular limitation. In one example, the first reflecting layer 11preferably contains, as a main component, a metal having a highreflectance, such as silver or aluminum, more preferably contains silveras a main component. The first reflecting layer 11 may be of an alloy.In particular, the metal constituting the first reflecting layer 11 ispreferably a silver alloy containing palladium and copper. The firstreflecting layer 11 composed of such a silver alloy has excellentdiscoloration resistance in the air. In an embodiment of the presentinvention, “containing as a main component” refers to containing apredetermined component at 50 to 100 mass %.

The first reflecting layer 11 is not limited to any particularthickness. For example, the first reflecting layer 11 preferably has athickness of 10 nm or more, more preferably 50 nm or more. In addition,the first reflecting layer 11 preferably has a thickness of 1000 nm orless, more preferably 500 nm or less. The first reflecting layer 11having a thickness of 10 nm or more makes it possible that thescintillator panel 2 achieves sufficient light blocking, thus affordingan image having higher sharpness. The first reflecting layer 11 having athickness of 1000 nm or less makes it less likely to make the roughnessof the surface of the first reflecting layer 11 large, and to decreasethe reflectance.

(Protective Layer)

A scintillator panel according to an embodiment of the present inventionpreferably has a protective layer 12 on the surface of the firstreflecting layer 11. Even in cases where, for example, an alloy lackingin discoloration resistance in the air is used for the first reflectinglayer 11, providing the protective layer 12 makes it possible todecrease the discoloration, to inhibit the reflectance of the firstreflecting layer 11 from being decreased by reaction between the firstreflecting layer 11 and the phosphor layer 6, and to further enhance thebrightness. The protective layer 12 may be further provided between thebarrier rib 5 and the first reflecting layer 11. Providing theprotective layer 12 between the barrier rib 5 and the first reflectinglayer 11 makes it possible to inhibit the reflectance of the firstreflecting layer 11 from being decreased by reaction between the barrierrib 5 and the first reflecting layer 11, and to further enhance thebrightness.

For the protective layer 12, any of an inorganic protective layer and anorganic protective layer can be used suitably. An inorganic protectivelayer and an organic protective layer can be combined into a laminate,and used as the protective layer 12.

(Inorganic Protective Layer)

An inorganic protective layer has low water-vapor permeability, andhence, is suitable as the protective layer 12. An inorganic protectivelayer can be formed by a known technique such as a sputtering method.The inorganic protective layer is not limited to any particularmaterial. Examples of materials for an inorganic protective layerinclude: oxides such as silicon oxide, indium tin oxide, and galliumzinc oxide; nitrides such as silicon nitride; fluorides such asmagnesium fluoride; the like. Among these, silicon oxide or siliconnitride is preferably used as a material for an inorganic protectivelayer because of having low water-vapor permeability and in addition,being less prone to decrease the reflectance of silver in the formationof an inorganic protective layer.

The inorganic protective layer is not limited to any particularthickness. For example, the inorganic protective layer preferably has athickness of 2 nm or more, more preferably 5 nm or more. In addition,the inorganic protective layer preferably has a thickness of 300 nm orless, more preferably 100 nm or less. Having a thickness of 2 nm or moremakes it possible to increase the effect of inhibiting the brightness ofthe scintillator panel 2 from decreasing in a high-temperature andhigh-humidity environment. Having a thickness of 300 nm or less makes itpossible to inhibit coloration from being caused by the inorganicprotective layer, and to further enhance the brightness. The thicknessof the inorganic protective layer can be measured in the same method asthe thickness of the below-mentioned organic protective layer.

(Organic Protective Layer)

The organic protective layer is preferably a polymer compound havingexcellent chemical durability, and preferably contains, for example, apolysiloxane or an amorphous fluorine resin as a main component.

In an embodiment of the scintillator panel, examples of polysiloxanesinclude a hydrolysate or partial condensate of an organosilane thatencompasses an organosilane represented by the general formula (3).

In the general formula (3), R² represents a monovalent organic grouphaving at least one of an epoxy group and an acid anhydride group. R³and R⁴ independently represents hydrogen, a C₁-C₆ alkyl group, C₂-C₆acyl group, or C₆-C₁₆ aryl group. m represents an integer of 1 to 3. nrepresents an integer of 0 to 2. m+n is 1 to 3. When m is 2 or greater,a plurality of R²s may be the same or different. Additionally, when n is2, a plurality of R³s may be the same or different. Additionally, whenm+n is 2 or smaller, a plurality of R⁴s may be the same or different.

An amorphous fluorine resin has excellent solvent solubility, and hence,can be easily formed using a known technique, for example, performingsolution application or spray coating on the protective layer 12. Here,that “a fluorine resin is amorphous” means that, as afluorine-containing resin is measured by powder X-ray diffraction, nosubstantial peak attributable to a crystal structure is observed, andthat only a broad halo is observed.

The amorphous fluorine resin is preferably a copolymer having, as arepeating unit, a structure represented by the general formula (4), orhaving two different structures including a structure of the generalformula (4).

In cases where the amorphous fluorine resin is a copolymer, thecopolymer may be any one of an alternating copolymer, block copolymer,and random copolymer.

In the general formula (4), X represents oxygen, j and k independentlyrepresent 0 or 1, and p is an integer of 1 or greater.

In the general formula (4), R⁵ to R⁸ independently represent hydrogen,halogen, a substituted or unsubstituted alkyl group, substituted orunsubstituted alkenyl group, substituted or unsubstituted alkynyl group,hydroxyl group, substituted or unsubstituted alkoxy group, substitutedor unsubstituted aryl group, cyano group, aldehyde group, substituted orunsubstituted ester group, acyl group, carboxyl group, substituted orunsubstituted amino group, nitro group, or substituted or unsubstitutedepoxy group. At least one of R⁵ and R⁶ is preferably fluorine. Inaddition, at least one of R⁷ and R⁸ is preferably fluorine.

In the general formula (4), j and k represent the number of oxygens.However, in cases where j or k is 0, Xj or Xk is a single bond. When atleast one of j and k is 1, the glass transition temperature is suitable,and hence, such j and k are preferable.

In the general formula (4), p represents a repeating number, and ispreferably 1 to 4, more preferably 1 to 3. Additionally, in cases wheret is 2 or greater, a plurality of R⁷s and R⁸s may the same or different.

In the general formula (4), the alkyl group preferably has 1 to 8 carbonatoms. The alkenyl group preferably has 1 to 12 carbon atoms. The alkoxygroup preferably has 1 to 10 carbon atoms. The aryl group preferably has5 to 15 carbon atoms.

The organic protective layer preferably has a thickness of 0.05 μm ormore, more preferably 0.2 μm or more. In addition, the organicprotective layer preferably has a thickness of 10 μm or less, morepreferably 5 μm or less. The organic protective layer having a thicknessof 0.05 μm or more makes it possible to increase the effect ofinhibiting the brightness of the scintillator panel 2 from decreasing.In addition, the organic protective layer having a thickness of 10 μm orless makes it possible that, in the scintillator panel 2, the cell isincreased in volume, and packed with a sufficient amount of the phosphor14, and thus that the brightness is further enhanced. In an embodimentof the present invention, the thickness of the organic protective layercan be measured by observation under a scanning electron microscope. Inthis regard, the organic protective layer formed in the below-mentionedorganic protective layer forming step tends to have a smaller thicknesson the side of the barrier rib near the top and a larger thickness onthe side of the barrier rib near the bottom. Accordingly, in cases wherethe thickness varies in such a manner, the thickness of the organicprotective layer refers to the thickness on the side of the barrier rib5 at the central portion in the height direction.

(Second Reflecting Layer)

In a scintillator panel according to an embodiment of the presentinvention, the protective layer 12 preferably has a second reflectinglayer (second reflecting layer) 13 on the surface thereof. The secondreflecting layer 13 is preferably provided on at least a part of theprotective layer 12. Providing the second reflecting layer 13 makes iteasier that light emitted by the phosphor layer 6 emerges on the surfacemore efficiently, and thus, the brightness of the scintillator panel 2is enhanced further.

The second reflecting layer 13 preferably contains a metal oxide, andthe metal oxide is subject to no particular limitation. In one example,the second reflecting layer 13 preferably contains, as a main component,a metal oxide having a high refractive index, such as titanium oxide,zirconium oxide, zinc oxide, or aluminum oxide, and more preferablycontains titanium oxide as a main component. In an embodiment of thepresent invention, “containing as a main component” refers to containinga predetermined component at 50 to 100 mass %.

The metal oxide is preferably has a refractive index of 1.6 or more,more preferably 1.8 or more. Having a refractive index of 1.6 or moremakes it possible that the difference in the refractive index betweenthe metal oxide and the air is increased, and that the reflectance ismore easily enhanced at the second reflecting layer 13.

The metal oxide preferably has a particulate shape. Having a particulateshape makes it less likely that, when light emitted by the phosphorlayer is reflected by the reflecting layer, the reflectance varies, andmakes it more likely that the light emitted emerges on the surface moreefficiently, thus further enhancing the brightness of the scintillatorpanel 2.

In cases where the metal oxide has a particulate shape, the averageparticle diameter thereof is preferably 100 to 1000 nm, more preferably150 to 700 nm. The metal oxide having an average particle diameter of100 nm or more further enhances the reflectance with respect to thewavelength of light emitted by the phosphor, and thus enhancing thebrightness more easily. On the other hand, having an average particlediameter of 1000 nm or less allows the density of the particles in thesecond reflecting layer to be larger, and even if the layer is a thinfilm, the reflectance is enhanced further, and thus, the brightness ismore likely to be enhanced.

Here, the average particle diameter of a metal oxide in the presentinvention refers to a particle diameter corresponding to 50% in thecumulative distribution of the particle size, and can be measured usinga particle size distribution analyzer (for example, an MT3300manufactured by Nikkiso Co., Ltd.). More specifically, a metal oxide isintroduced into a sample chamber filled with water, and ultrasonicatedfor 300 seconds. Then, a measurement is made of a particle sizedistribution, according to which the particle diameter corresponding to50% in the cumulative distribution is regarded as the average particlediameter.

The second reflecting layer 13 may contain a polymer compound other thana metal oxide. The second reflecting layer 13 containing a polymercompound makes it more likely that, in the below-mentioned phosphorlayer packing step, the second reflecting layer 13 is inhibited frombeing detached from the protective layer 12, and that the metal oxideparticles in the second reflecting layer 13 is inhibited from beingdetached.

(Phosphor Layer)

A scintillator panel according to an embodiment of the present inventionhas a phosphor in a cell defined by the barrier rib.

The phosphor layer 6 absorbs the energy of radiation such as incidentX-rays, and emits electromagnetic waves in the wavelength range of from300 nm to 800 nm, that is, light in the range of from ultraviolet lightto infrared light with visible light in the center therebetween. Thelight emitted by the phosphor layer 6 is photoelectrically converted inthe photoelectric conversion layer 8, and outputted as electric signalsthrough the output layer 9. The phosphor layer 6 preferably has aphosphor 14 and a binder resin 15.

(Phosphor)

The phosphor 14 is not subject to any particular limitation. Examples ofthe phosphor 14 include sulfide phosphors, germanate phosphors, halidephosphors, barium sulfate phosphors, hafnium phosphate phosphors,tantalate phosphors, tungstate phosphors, rare earth silicate phosphors,rare earth oxysulfide phosphors, rare earth phosphate phosphors, rareearth oxyhalide phosphors, alkaline earth metal phosphate phosphors, andalkaline earth metal fluorohalide phosphors. Examples of rare earthsilicate phosphors include cerium-activated rare earth silicatephosphors. Examples of rare earth oxysulfide phosphors includepraseodymium-activated rare earth oxysulfide phosphors,terbium-activated rare earth oxysulfide phosphors, andeuropium-activated rare earth oxysulfide phosphors. Examples of rareearth phosphate phosphors include terbium-activated rare earth phosphatephosphors. Examples of rare earth oxyhalogen phosphors includeterbium-activated rare earth oxyhalide phosphors and thulium-activatedrare earth oxyhalide phosphors. Examples of alkaline earth metalphosphate phosphors include europium-activated alkaline earth metalphosphate phosphors. Examples of alkaline earth metal fluorohalidephosphors include europium-activated alkaline earth metal fluorohalidephosphors. The phosphor 14 may be a combination of these. Among these, apreferable phosphor as the phosphor 14 is selected from halidephosphors, praseodymium-activated rare earth oxysulfide phosphor,terbium-activated rare earth oxysulfide phosphors, andeuropium-activated rare earth oxysulfide phosphors from the viewpoint ofhigh light emission efficiency. A phosphor selected frompraseodymium-activated rare earth oxysulfide phosphors andterbium-activated rare earth oxysulfide phosphors is more preferable.

The phosphor 14 preferably has an average particle diameter of 0.5 to 50μm, more preferably 3.0 to 40 μm, still more preferably 4.0 to 30 μm.The phosphor having an average particle diameter of 0.5 μm or more makesit possible to further enhance the efficiency of converting radiationinto visible light, and to further enhance the brightness. In addition,such an average particle diameter makes it possible to inhibit theagglomeration of the phosphor particles. On the other hand, the phosphorhaving an average particle diameter of 50 μm or less enables the surfaceof the phosphor layer to have excellent smoothness, and makes itpossible to inhibit a bright spot from being generated on the image.

Here, the average particle diameter of the phosphor 14 in the presentinvention refers to a particle diameter corresponding to 50% in thecumulative distribution of the particle size, and can be measured usinga particle size distribution analyzer (for example, MT3300 manufacturedby Nikkiso Co., Ltd.). More specifically, a phosphor is introduced intoa sample chamber filled with water, and ultrasonicated for 300 seconds.Then, a measurement is made of a particle size distribution, accordingto which the particle diameter corresponding to 50% in the cumulativedistribution is regarded as the average particle diameter.

(Binder Resin)

The binder resin 15 is subject to no particular limitation. Examples ofthe binder resin 15 include thermoplastic resins, thermosetting resins,photo-curable resins, and the like. More specific examples of the binderresin 15 include: acrylic resins; acetal resins; cellulose derivatives;polysiloxane resins; epoxy compounds; melamine resins; phenolic resins;urethane resins; urea resins; vinyl chloride resins; polyvinyl acetal;polyester resins such as polyethylene terephthalate and polyethylenenaphthalate; polyethylene; polypropylene; polycarbonate; polystyrene;polyvinyl toluene; and polyphenyl benzene; and the like. From amongthese, the binder resin 15 preferably contains at least one of acrylicresins, epoxy resins, cellulose derivatives, epoxy resins, polyvinylacetal, and polyester resins, and more preferably contains one to threeof these as (a) main component(s). This makes it possible to inhibitlight from being attenuated in a cell in the scintillator panel 2, thusmaking it easier to take out emitted light sufficiently. In this regard,containing, as (a) main component(s), at least one of acrylic resins,cellulose derivatives, epoxy resins, polyvinyl acetal, and polyesterresins means that the total amount of the acrylic resin, cellulosederivative, epoxy resin, polyvinyl acetal, and polyester resin is 50 to100 mass % of the materials constituting the resin.

The binder resin 15 is preferably in contact with the protective layer12. In this case, the binder resin 15 is preferably in contact with atleast a part of the protective layer 12. This makes it less likely thatthe phosphor 14 comes off a cell in the scintillator panel 2. In thisregard, as depicted in FIG. 1 , the binder resin 15 may be packed withalmost no space in a cell, or may be packed with some space.

As above-mentioned, a scintillator panel 2 according to an embodiment ofthe present invention makes it possible to obtain an image having highbrightness and high sharpness.

(Method of Producing Scintillator Panel)

A method of producing a scintillator panel according to an embodiment ofthe present invention includes: a barrier rib forming step of forming abarrier rib on a substrate to define cells; a reflecting layer formingstep of forming a metal reflecting layer on the surface of said barrierrib; a packing step of packing a phosphor in the cells defined by saidbarrier rib; wherein said barrier rib contains one or more compounds (P)selected from the group consisting of polyimides, polyamides,polyamideimides, and polybenzoxazoles and a structure derived from anepoxy compound. Below, each step will be described. In this regard, thedescription of the matters corresponding to the matters described in theabove-mentioned embodiments of a scintillator panel will be omitted fromthe following description as appropriate.

(Barrier Rib Forming Step)

The barrier rib forming step is a step in which the barrier rib isformed on a substrate to define cells. A method of forming the barrierrib on the substrate is subject to no particular limitation. The barrierrib contains the above-mentioned compound (P) and a structure derivedfrom an epoxy compound. As a method of forming a barrier rib, any kindof known method can be utilized. Photolithography is preferable from theviewpoint of easy shape control.

In a method of forming a barrier rib containing the compound (P), abarrier rib can be formed, for example, by the following: a coating stepin which the surface of a substrate is coated with a photosensitiveresin composition containing the compound (P) to obtain a coating film;and a pattern forming step in which the coating film is exposed anddeveloped to obtain a barrier rib pattern.

The coating step is a step in which the surface of the substrate iswholly or partially coated with the above-mentioned photosensitive resincomposition to obtain a coating film. Examples of a method of applying aphotosensitive resin composition include a screen printing method, a barcoater method, a roll coater method, a die coater method, and a bladecoater method. The thickness of the coating film to be obtained can beadjusted by the number of times of application, the mesh size of thescreen, the viscosity of the photosensitive resin composition, or thelike.

Next, the photosensitive resin composition coating film formed by theabove-mentioned method is irradiated with actinic rays through a maskhaving a desired pattern, and thus exposed. Examples of actinic rays tobe used for the exposure include ultraviolet rays, visible rays, anelectron beam, X rays, or the like. In the present invention, the i-line(365 nm), h-line (405 nm), or g-line (436 nm) of the mercury lamp ispreferably used.

To form a pattern, the exposure is followed by removing the exposedportion with a developer. Examples of preferable developers include: anaqueous solution of tetramethylammonium hydroxide; and an aqueoussolution of a compound exhibiting alkalinity, such as diethanol amine,diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodiumcarbonate, potassium carbonate, triethylamine, diethylamine,methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine,ethylenediamine, or hexamethylenediamine. In addition, such an aqueousalkali solution optionally contains the following: a polar solvent suchas N-methyl-2-pyrrolidone, NN-dimethylformamide, N,N-dimethyl acetamide,dimethyl sulfoxide, γ-butyrolactone, or dimethylacrylamide; an alcoholsuch as methanol, ethanol, or isopropanol; an ester such as ethyllactate or propylene glycol monomethyl ether acetate; a ketone such ascyclopentanone, cyclohexanone, isobutyl ketone, or methylisobutylketone; or the like. The solution may contain these singly or incombination of two or more kinds thereof.

The development can be performed, for example, by the following method:spraying the above-mentioned developer onto the coating face; buildingup a developer on the coating film face; immersing the coating film in adeveloper; or such immersion followed by ultrasonication. Thedevelopment conditions such as the developing time and the temperatureof the developer in the developing step are preferably conditions thatmake it possible to form a pattern with the exposed portion removed.

The development is preferably followed by a rinsing treatment withwater. Here, the rinsing treatment may be performed with watersupplemented with the following: an alcohol such as ethanol or isopropylalcohol; an ester such as ethyl lactate or propylene glycol monomethylether acetate; or the like.

In addition, the development may be preceded by a baking treatment, asrequired. This results in enhancing the resolution of the patterndeveloped and increases the tolerable range of the developmentconditions in some cases. The baking temperature is preferably in therange of from 50 to 180° C., more preferably in the range of from 60 to120° C., in particular. The time is preferably 5 seconds to severalhours.

After the pattern is formed, the unreacted cationic polymerizablecompound and the cationic polymerization initiator remain in the coatingfilm of the photosensitive resin composition. Because of this, there aresome cases where these are thermally decomposed to generate gas duringthe below-mentioned thermal cross-linking reaction. To avoid this, it ispreferable that the whole face of the resin composition coating afterthe formation of the pattern is irradiated with the above-mentionedexposure light to generate acid from the cationic polymerizationinitiator. Such an operation makes it possible that, during the thermalcross-linking reaction, the reaction of the unreacted cationicpolymerizable compound progresses, so that the generation of gas derivedfrom the thermal decomposition is inhibited.

After the development, a temperature of 120° C. to 300° C. is applied toallow the thermal cross-linking reaction to progress. The cross-linkingmakes it possible to enhance the heat resistance and the chemicalresistance. A method for this heating treatment can be selected from thefollowing: a method in which the temperature is raised stepwise to atemperature selected; or a method in which the treatment is performedfor 5 minutes to 5 hours while the temperature is continuously raisedwithin a temperature range selected.

In a method of producing a scintillator panel according to an embodimentof the present invention, the base material used during the formation ofa barrier rib may be used as a substrate of the scintillator panel, orit is also possible that a barrier rib is formed on a support, thebarrier rib is peeled from the support, and then, the barrier rib peeledoff is mounted on a substrate, and used. A method that can be used topeel the barrier rib from the base material is any known technique suchas a technique in which a peeling assisting layer is provided betweenthe base material and the barrier rib.

In a method of producing a scintillator panel according to an embodimentof the present invention, the substrate may keep fixed to the supportwhen the barrier rib is formed. Fixing the substrate to the supportmakes it possible to retain the smoothness of the substrate, thus makingit possible to decrease variations in the height of the barrier rib inthe barrier rib forming step.

It is preferable that the substrate can be peeled from the support afterthe below-mentioned step of producing a scintillator panel. Enabling thesubstrate to be peeled from the support makes it possible to inhibit thesupport from absorbing the radiation incident on the scintillator panel.This results in making it possible to provide a sufficient dose ofradiation incident on the scintillator panel, and thus enhancing thebrightness further.

The support is not limited to any particular material as long as thesupport has higher mechanical strength than the substrate and hassmoothness. The support is preferably glass.

The thickness of the support can be adjusted suitably, as required, andis preferably 0.3 mm or more, more preferably 0.5 mm or more, from amechanical strength viewpoint.

A method of fixing the substrate to the support is subject to noparticular limitation as long as the method is a known method. Examplesof a method of fixing a substrate composed of a polymer material to aglass support include: a method in which an adhesive tape is bonded tothe periphery of the substrate; a method in which the surface of one ofthe materials is coated with a liquid resin, with which the other isbrought in contact and bonded; a method in which an adhesive film isbonded to one of the materials, to which film the other is bonded underpressure; a method in which one of the materials is surface-treated andfixed by intermolecular interaction; and the like. Among these, a methodin which an adhesive film is bonded to one of the materials, to whichfilm the other is bonded under pressure is preferable.

In addition, examples of a method of fixing a glass substrate to a glasssupport include: a method in which one of the materials issurface-treated and fixed by intermolecular interaction; a method inwhich a layer containing a low-melting-point glass is formed on one ofthe materials, and fixed to the other by sintering; and the like. Amongthese, a method in which a layer containing a low-melting-point glass isformed on one of the materials, and fixed to the other by sintering ispreferable.

(Reflecting Layer Forming Step)

A scintillator panel according to an embodiment of the present inventionincludes a reflecting layer forming step of forming a metal reflectinglayer (first reflecting layer) on the surface of the barrier rib. Thefirst reflecting layer is preferably formed on at least a part of thebarrier rib.

The first reflecting layer is not limited to any particular formingmethod. For example, the first reflecting layer can be formed by thefollowing: a vacuum film-forming method such as a vacuum evaporationmethod, sputtering method, or CVD method; a plating method; a pasteapplication method; or a spray method based on spraying. Among these, asputtering method is preferable because a first reflecting layer formedby a sputtering method has higher reflectance uniformity and corrosionresistance than the first reflecting layer formed by another technique.

(Inorganic Protective Layer Forming Step)

In this regard, a method of producing a scintillator panel according toan embodiment of the present invention may include an inorganicprotective layer forming step of forming an inorganic protective layeron the surface of the reflecting layer. The inorganic protective layeris not limited to any particular forming method. For example, theinorganic protective layer can be formed by the following: a vacuumfilm-forming method such as a vacuum evaporation method, sputteringmethod, or CVD method; a paste application method; or a spray methodbased on spraying. Among these, a sputtering method is preferablebecause an inorganic protective layer formed by a sputtering method hashigher uniformity and corrosion resistance than the inorganic protectivelayer formed by another technique.

(Organic Protective Layer Forming Step)

A method of producing a scintillator panel according to an embodiment ofthe present invention may include an organic protective layer formingstep of forming an organic protective layer on the surface of thereflecting layer. The organic protective layer is not limited to anyparticular forming method. For example, an organic protective layer canbe formed by applying a solution of a polysiloxane or an amorphousfluorine-containing resin to the barrier rib substrate under vacuum, andthen drying the solution to remove the solvent.

In cases where a polysiloxane is used, the substrate dried is preferablycured at a higher temperature than the drying temperature. Through thecuring, the substrate undergoes the progress of condensation of thepolysiloxane, thus making it easier to enhance the heat resistance andthe chemical resistance, and to enhance the initial brightness of thescintillator panel.

(Second Reflecting Layer Forming Step)

A method of producing a scintillator panel according to an embodiment ofthe present invention may include a second reflecting layer forming stepof forming a second reflecting layer on the surface of the inorganicprotective layer or the organic protective layer. The second reflectinglayer is not limited to any particular forming method. In light of thesimplicity of the process and the capability of forming a secondreflecting layer homogeneously over a large area, one example is amethod in which a second reflecting layer paste obtained by mixing ametal oxide powder and a resin with a solvent is applied to a barrierrib substrate under vacuum, then drying the paste to remove the solvent.

(Packing Step)

A method of producing a scintillator panel according to an embodiment ofthe present invention includes a packing step of packing a phosphor in acell defined by the barrier rib. The method of packing a phosphor issubject to no particular limitation. In light of the simplicity of theprocess and the capability of packing a phosphor homogeneously over alarge area, one example of such a packing method is preferably a methodin which a phosphor paste obtained by mixing a phosphor powder and abinder resin with a solvent is applied to a barrier rib substrate undervacuum, then drying the paste to remove the solvent.

As above-mentioned, a method of producing a scintillator panel accordingto an embodiment of the present invention makes it possible that theresulting scintillator affords an image having high brightness and highsharpness.

EXAMPLES

The present invention will be described in more detail below by way ofExamples and Comparative Examples. The present invention is not to belimited thereto. The compounds used in Examples and Comparative Exampleswere synthesized by the below-mentioned methods.

(Barrier Rib Material)

Synthesis Example 1

(Raw Materials for Polyimide A)

Amine compound: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(hereinafter referred to as BAHF, manufactured by Tokyo ChemicalIndustry Co., Ltd.)

Acid anhydride: RIKACID (registered trademark) TDA-100 (manufactured byNew Japan Chemical Co., Ltd.)

Solvent: γ-butyrolactone (hereinafter referred to as GBL, manufacturedby Fujifilm Wako Pure Chemical Corporation)

(Synthesis of Polyimide A)

Under a dry nitrogen gas stream, 29.30 g (0.08 mol) of BAHF was added to80 g of GBL, and dissolved with stirring at 120° C. Next, to theresulting mixture, 30.03 g (0.1 mol) of TDA-100 together with 20 g ofGBL was added, and the resulting mixture was stirred at 120° C. for 1hour, and then stirred at 200° C. for 4 hours to obtain a reactionsolution. Next, the reaction solution was added to 3 L of water togather a white precipitate. This precipitate was collected byfiltration, washed with water three times, and then dried with a vacuumdryer at 80° C. for 5 hours to obtain a polyimide A.

Synthesis Example 2

(Raw Materials for Polyamide A)

Amine compound: BAHF (manufactured by Tokyo Chemical Industry Co., Ltd.)

Acid chloride: 4,4′-diphenyl ether dicarboxylic dichloride (manufacturedby Tokyo Chemical Industry Co., Ltd.)

Solvent: N-methyl-2-pyrrolidone (hereinafter referred to as NMP,manufactured by Fujifilm Wako Pure Chemical Corporation)

(Synthesis of Polyamide A)

Under a dry nitrogen gas stream, 29.3 g (0.08 mol) of BAHF was added to100 g of NMP, and dissolved with stirring at room temperature. Then,with the reaction solution temperature maintained at −10 to 0° C., 29.5g (0.1 mol) of 4,4′-diphenyl ether dicarboxylic dichloride was added insmall installments to the solution. Upon completion of the addition, theresulting mixture was heated to room temperature, and continued to bestirred for 3 hours. Next, the reaction solution was added to 3 L ofwater to gather a white precipitate. This precipitate was collected byfiltration, washed with water three times, and then dried with a vacuumdryer at 80° C. for 5 hours to obtain a polyamide A.

Synthesis Example 3

(Raw Materials for Polyamideimide A)

Amine compound: BAHF (manufactured by Tokyo Chemical Industry Co., Ltd.)

Acid anhydride: RIKACID (registered trademark) TDA-100 (manufactured byNew Japan Chemical Co., Ltd.)

Acid chloride compound: 3-nitrobenzoyl chloride (manufactured by TokyoChemical Industry Co., Ltd.)

Reactive compound: propylene oxide (manufactured by Fujifilm Wako PureChemical Corporation)

Solvent A: acetone (manufactured by Tokyo Chemical Industry Co., Ltd.)

Solvent B: methylcellosolve (manufactured by Tokyo Chemical IndustryCo., Ltd.)

Solvent C: GBL (manufactured by Fujifilm Wako Pure Chemical Corporation)

(Synthesis of Hydroxyl-Group-Containing Diamine Compound (a))

BAHF in an amount of 18.3 g (0.05 mol) was dissolved in 100 mL ofacetone and 17.4 g (0.3 mol) of propylene oxide, and the resultingsolution was cooled to −15° C. To this, a solution of 20.4 g (0.11 mol)of 3-nitrobenzoyl chloride dissolved in 100 mL of acetone was addeddropwise. Upon completion of the dropwise addition, the resultingmixture was allowed to react at −15° C. for 4 hours, and then, returnedto room temperature. A white solid precipitated was collected byfiltration and dried in vacuo at 50° C.

The resulting white solid in an amount of 30 g was introduced in a 300mL stainless-steel autoclave, and dispersed in 250 mL ofmethylcellosolve, and to the resulting dispersion liquid, 2 g of 5%palladium-carbon was added. Into this, hydrogen was introduced from aballoon, and a reduction reaction was allowed to progress at roomtemperature. After approximately two hours, no more deflation of theballoon was ascertained, and the reaction was terminated. Uponcompletion of the reaction, a palladium compound as a catalyst wasremoved by filtration, and the resulting product was concentrated with arotary evaporator to obtain a hydroxyl-group-containing diamine compound(a).

(Synthesis of Polyamideimide A)

Under a dry nitrogen gas stream, 31.4 g (0.08 mol) of thehydroxyl-group-containing diamine compound (a) was added to 80 g of GBL,and the resulting mixture was stirred at 120° C. Next, to the resultingmixture, 30.0 g (0.1 mol) of TDA-100 together with 20 g of GBL wasadded, and the resulting mixture was stirred at 120° C. for 1 hour, andthen stirred at 200° C. for 4 hours to obtain a reaction solution. Next,the reaction solution was added to 3 L of water to gather a whiteprecipitate. This precipitate was collected by filtration, washed withwater three times, and then dried with a vacuum dryer at 80° C. for 5hours to obtain a polyamideimide A.

Synthesis Example 4

(Raw Materials for Polybenzoxazole Precursor A)

Raw material A: diphenyl ether-4,4′-dicarboxylic acid (manufactured byTokyo Chemical Industry Co., Ltd.).

Raw material B: 1-hydroxy-1,2,3-benzotriazole (manufactured by TokyoChemical Industry Co., Ltd.)

Amine compound: BAHF (manufactured by Tokyo Chemical Industry Co., Ltd.)

Acid anhydride: 5-norbornene-2,3-dicarboxylic anhydride (manufactured byTokyo Chemical Industry Co., Ltd.).

Solvent A: N-methyl-2-pyrrolidone (hereinafter referred to as NMP,manufactured by Fujifilm Wako Pure Chemical Corporation)

Solvent B: methanol (manufactured by Tokyo Chemical Industry Co., Ltd.).

(Synthesis of Polybenzoxazole Precursor A)

Under a dry nitrogen gas stream, 0.16 mol of a mixture of a dicarboxylicacid derivative obtained by allowing 41.3 g (0.16 mol) of diphenylether-4,4′-dicarboxylic acid and 43.2 g (0.32 mol) of1-hydroxy-1,2,3-benzotriazole to react and 73.3 g (0.20 mol) of BAHFwere dissolved in 570 g of NMP, and then, the resulting mixture wasallowed to react at 75° C. for 12 hours. Next, to the resulting mixture,13.1 g (0.08 mol) of 5-norbornene-2,3-dicarboxylic anhydride dissolvedin 70 g of NMP was added. The resulting mixture was further stirred for12 hours, and the reaction was terminated. After the reaction mixturewas filtrated, the reaction mixture was introduced into a solutioncontaining water and methanol at 3:1 (by volume ratio) to obtain a whiteprecipitate. This precipitate was collected by filtration, washed withwater three times, and then dried with a vacuum dryer at 80° C. for 24hours to obtain a polybenzoxazole precursor A.

Synthesis Example 5

(Raw Materials for Polyimide B)

Amine compound: BAHF (manufactured by Tokyo Chemical Industry Co., Ltd.)

Acid anhydride: RIKACID (registered trademark) TDA-100 (manufactured byNew Japan Chemical Co., Ltd.)

Solvent: GBL (manufactured by Fujifilm Wako Pure Chemical Corporation)

(Synthesis of Polyimide B)

Under a dry nitrogen gas stream, 36.63 g (0.1 mol) of BAHF was added to80 g of GBL, and dissolved with stirring at 120° C. Next, to theresulting mixture, 24.02 g (0.08 mol) of TDA-100 together with 20 g ofGBL was added, and the resulting mixture was stirred at 120° C. for 1hour, and then stirred at 200° C. for 4 hours to obtain a reactionsolution. Next, the reaction solution was added to 3 L of water togather a white precipitate. This precipitate was collected byfiltration, washed with water three times, and then dried with a vacuumdryer at 80° C. for 5 hours to obtain a polyimide B.

(Raw Materials for Photosensitive Polyimide Varnish)

Polyimide A: polyimide containing a carboxylic residue as an end of themolecular chain

Polyamide A: polyamide containing a carboxylic residue as an end of themolecular chain

Polyamideimide A: polyamideimide containing a carboxylic residue as anend of the molecular chain

Polybenzoxazole precursor A: polybenzoxazole precursor containing acarboxylic residue as an end of the molecular chain

Polyimide B: polyimide containing an amine residue as an end of themolecular chain

Phenolic resin A: “MARUKA LYNCUR” (registered trademark) M (manufacturedby Maruzen Petrochemical Co., Ltd.)

Epoxy resin A: “jER” (registered trademark) 630 (manufactured byMitsubishi Chemical Corporation)

Epoxy compound A: “TEPIC” (registered trademark) -VL (manufactured byNissan Chemical Corporation)

Epoxy compound B: “CELLOXIDE” (registered trademark) 2081 (manufacturedby Daicel Corporation)

Epoxy compound C: “SHOFREE” (registered trademark) PETG (manufactured byShowa Denko K.K.)

Acryl compound A: BP-6EM (manufactured by Kyoeisha Chemical Co., Ltd.)

Acryl compound B: “KAYARAD” (registered trademark) DPHA (manufactured byNippon Kayaku Co., Ltd.)

Photo-acid generator A: “CPI” (registered trademark) -310B (manufacturedby San-Apro Ltd.)

Photo-acid generator B: “CPI” (registered trademark) -410S (manufacturedby San-Apro Ltd.)

Photo-radical polymerization initiator A: OXE02 (manufactured by CibaSpecialty Chemicals Co., Ltd.)

Silane coupling agent: KBM-403 (manufactured by Shin-Etsu Chemical Co.,Ltd.)

(Measurement of Arithmetic Average Slope Angle)

A barrier rib substrate having a reflecting layer formed thereon was cutto give a cross section on which the reflecting layer on the side of thebarrier rib was bared. Using a laser microscope VK-X200 (manufactured byKeyence Corporation), five places on the side of the barrier rib werephotographed through an objective lens at a magnification ratio of 50×.A line roughness analysis was performed on a 20 μm long range in thecenter of the side of the barrier rib using the accessory analysissoftware. The average of the values of the five places was determinedand regarded as an arithmetic average slope angle. Here, the arithmeticaverage slope angle is determined by arithmetically averaging a slope(slope angle) made by each minute portion of a curve given by measuringthe surface shape. The smaller the value of the arithmetic average slopeangle, the smoother the surface shape.

(Evaluation of Reflectance)

A spectrocolorimeter CM-2600D (manufactured by Konica Minolta, Inc.) wasdisposed on the surface of each scintillator panel having no packedphosphor layer yet, and the reflectance in the range of from 400 to 700nm was measured using the SCI method. In respect of the resultingreflectance, the value at 550 nm was regarded as a value of reflectanceof the first reflecting layer. Additionally, a relative value withrespect to the reflectance in Comparative Example 1 as 100 wascalculated, and regarded as the reflectance of the first reflectinglayer. In Example 10, the reflectance obtained was regarded as a valueof reflectance of the second reflecting layer, and a relative value withrespect to the reflectance in Comparative Example 1 as 100 wascalculated, and regarded as the reflectance of the second reflectinglayer.

(Evaluation of Brightness)

Each scintillator panel having a phosphor layer packed therein wasarranged in the center of the surface of the sensor of an X-ray detectorPaxScan 2520V (manufactured by Varex Imaging Corporation) in such amanner that the cells of the scintillator panel and the pixels of thesensor corresponded one-to-one to each other in alignment. An end of thesubstrate was fixed with an adhesive tape. Thus, a radiation detectorwas produced. To this detector, X rays from an X-ray radiation deviceL9181-02 (manufactured by Hamamatsu Photonics K.K.) were radiated underconditions based on a tube voltage of 50 kV and a distance of 30 cmbetween the X-ray tube and the detector, whereby an image was acquired.The average of the digital values of the 256×256 pixels in the center ofthe light-emitting position of the scintillator panel in the imageacquired was regarded as a brightness value. Thus, the brightness wasmeasured. The brightness was outputted in arbitrary units, and hence, arelative value with respect to the brightness in Comparative Example 1as 100 was calculated, and regarded as a brightness.

(Evaluation of Amount of X-Ray Absorption)

Each scintillator panel having a phosphor layer packed therein wasarranged on a detection unit of a Model EMF123 X-ray spectrometer(manufactured by EMF Japan Co., Ltd.). To this scintillator panel, Xrays from an X-ray radiation device L9181-02 (manufactured by HamamatsuPhotonics K.K.) were radiated under conditions based on a tube voltageof 50 kV and a distance of 30 cm between the X-ray tube and thedetector, during which a spectrum of the number of photons was acquired.The total number of photons of the spectrum acquired was regarded as theamount of X-ray transmission, and the amount of X-ray absorption of thescintillator panel was calculated from the total number of photonsacquired in cases where X rays were radiated under conditions where noscintillator panel was present. In Examples, a relative value withrespect to the amount of X-ray absorption in Comparative Example 1 as100 was calculated, and regarded as the amount of X-ray absorption.

(Measurement of Mechanical Strength)

Each scintillator panel having a phosphor layer packed therein wasdisposed on a stage of an optical microscope OPTIPHOT 300 (manufacturedby Nikon Corporation) in such a manner that the phosphor layer was onthe objective lens side. With respect to this scintillator panel, howthe top of the barrier rib was in the 500-pixel×500-pixel area in thecenter of the scintillator panel was observed. From the top of thebarrier rib observed, the number of places where deformation such aswrinkling, fracture, and/or breakage was/were caused was calculated. Interms of how the top of the barrier rib was, a scintillator thatunderwent deformation such as wrinkling, fracture, and/or breakage at 10places or less rated A, 11 to 20 places B, and 21 places or more C.

Example 1

(Preparation of Varnish)

In GBL, 10 g (2.0 mmol) of the polyimide A obtained in Synthesis Example1, 10 g (26.2 mmol) of the epoxy compound A (“TEPIC”-VL) as an epoxycompound, 0.6 g of the photo-acid generator A (“CPI”-310B) as aphoto-acid generator, and 0.8 g of KBM-403 as a silane coupling agentwere dissolved. The addition amount of the solvent was adjusted in sucha manner that the solid concentration was 60 wt %, assuming that theadditives other than the solvent were regarded as solids. Then, theresulting solution was filtrated under pressure with a filter having aretention particle diameter of 1 μm to obtain a photosensitive polyimidevarnish.

(Production of Barrier Rib Substrate)

A PI film, 125 mm×125 mm×0.05 mm, was used as a substrate. Thephotosensitive polyimide varnish was applied to the surface of thesubstrate using a die coater so as to have a thickness of 100 μm afterbeing dried. The varnish was dried to give a coating film of thephotosensitive polyimide varnish.

Next, the coating film of the photosensitive polyimide varnish wasexposed at a dose of 2000 mJ/cm² using a super high-pressure mercurylamp via a photomask (chromium mask having grid-like openings and havinga pitch of 127 μm and a line width of 10 μm) the openings of whichcorresponded to a desired pattern. The coating film after exposure wasdeveloped in an aqueous solution of 2 mass % potassium hydroxide, andthe unexposed portions were removed to obtain a grid-like pattern. Theresulting grid-like pattern was cured by thermal cross-linking in theair at 200° C. for 60 minutes to form grid-like barrier ribs. A crosssection of the barrier rib was bared by cutting, and photographed usinga scanning electron microscope S2400 (manufactured by Hitachi, Ltd.).The height, bottom width, and top width of the barrier rib and thedistance between the barrier ribs were measured.

(Formation of First Reflecting Layer and Inorganic Protective Layer)

A commercially available sputtering device and sputtering target wereused. The sputtering was performed under conditions where the thicknessof the metal would become 300 nm on a flat glass plate that was arrangedin the vicinity of the barrier rib substrate. For the sputtering target,APC (manufactured by Furuya Metal Co., Ltd.) that was a silver alloycontaining palladium and copper was used. After the first reflectinglayer was formed, SiN as a protective layer was formed in the samevacuum batch so as to have a thickness of 100 nm on a glass substrate.

(Formation of Organic Protective Layer)

Fluorine-Containing Resin Solution

With 1 part by mass of “CYTOP” (registered trademark) CTL-809M as anamorphous fluorine-containing resin, 1 part by mass of a fluorinesolvent CT-SOLV 180 (manufactured by AGC Inc.) as a solvent was mixed toproduce a resin solution.

This resin solution was vacuum-printed on the barrier rib substratehaving the first reflecting layer and the inorganic protective layerformed thereon. Then, the resulting product was dried at 90° C. for 1hour, and furthermore, cured at 190° C. for 1 hour to form an organicprotective layer. A triple ion milling device EMTIC3X (manufactured byLeica Microsystems GmbH) was used to bare a cross section of the barrierrib. The cross section was photographed under a field emission typescanning electron microscope (FE-SEM) Merlin (manufactured by Carl ZeissAG). The thickness of the organic protective layer on the side of thebarrier rib in the central portion in the height direction of thebarrier rib in the barrier rib substrate was measured and found to be 1μm.

(Phosphor)

Commercially available GOS: Tb phosphor powder (gadolinium oxysulfidedoped with Tb) was used directly. The average particle diameter D50measured using a particle size distribution analyzer MT3300(manufactured by NIKKISO Co., Ltd.) was 11 μm.

(Binder Resin of Phosphor Layer)

Raw materials used to produce a binder resin for a phosphor layer are asbelow-mentioned.

Binder resin: ETHOCEL (registered trademark) 7 cp (manufactured by TheDow Chemical Company)

Solvent: benzyl alcohol (manufactured by Fujifilm Wako Pure ChemicalCorporation)

(Formation of Phosphor Layer)

With 5 parts by mass of a binder resin solution having a concentrationof 10 mass %, 10 parts by mass of phosphor powder was mixed to produce aphosphor paste. This phosphor paste was vacuum-printed on the barrierrib substrate having a reflecting layer, inorganic protective layer, andorganic protective layer formed thereon, and packed in such a mannerthat the volume fraction of the phosphor was 65%. The phosphor paste wasdried at 150° C. for 15 minutes to form a phosphor layer.

Example 2

A varnish was prepared in the same manner as in Example 1 except thatthe polyamide A obtained in Synthesis Example 2 was used instead of thepolyimide A in Example 1. The barrier rib substrate was produced, andthen, the reflectance, brightness, and amount of X-ray absorption weremeasured.

Example 3

A varnish was prepared in the same manner as in Example 1 except thatthe polyamideimide A obtained in Synthesis Example 3 was used instead ofthe polyimide A in Example 1. The barrier rib substrate was produced,and then, the reflectance, brightness, and amount of X-ray absorptionwere measured.

Example 4

A varnish was prepared in the same manner as in Example 1 except thatthe polybenzoxazole precursor A obtained in Synthesis Example 4 was usedinstead of the polyimide A in Example 1. The barrier rib substrate wasproduced, and then, the reflectance, brightness, and amount of X-rayabsorption were measured.

Example 5

A varnish was prepared in the same manner as in Example 1 except thatthe epoxy compound B was used instead of the epoxy compound A inExample 1. The barrier rib substrate was produced, and then, thereflectance, brightness, and amount of X-ray absorption were measured.

Example 6

A varnish was prepared in the same manner as in Example 1 except thatthe epoxy compound C was used instead of the epoxy compound A inExample 1. The barrier rib substrate was produced, and then, thereflectance, brightness, and amount of X-ray absorption were measured.

Example 7

A varnish was prepared in the same manner as in Example 1 except thatthe photo-acid generator B was used instead of the photo-acid generatorA in Example 1. The barrier rib substrate was produced, and then, thereflectance, brightness, and amount of X-ray absorption were measured.

Example 8

A varnish was prepared in the same manner as in Example 1 except thatthe polyimide B obtained in Synthesis Example 5 was used instead of thepolyimide A in Example 1, that 10 g of the epoxy compound A (“TEPIC”-VL)was changed to 5.0 g of the acryl compound A (BP-6EM) and 0.6 g of theacryl compound B (“KAYARAD” DPHA), and that 0.6 g of the photo-acidgenerator A (“CPI”-310B) was changed to 1.4 g of the photo-radicalpolymerization initiator A (OXE02). The barrier rib substrate wasproduced, and then, the reflectance, brightness, and amount of X-rayabsorption were measured.

Example 9

A varnish was prepared in the same manner as in Example 1 except thatthe polyimide B obtained in Synthesis Example 5 was used instead of thepolyimide A in Example 1. The barrier rib substrate was produced, andthen, the reflectance, brightness, and amount of X-ray absorption weremeasured.

Example 10

A barrier rib substrate was produced in the same manner as in Example 1except that the second reflecting layer was formed by thebelow-mentioned method. The barrier rib substrate was produced, andthen, the reflectance, brightness, and amount of X-ray absorption weremeasured.

(Raw Materials for Second Reflecting Layer Paste)

Raw materials used to produce a second reflecting layer paste are asbelow-mentioned.

Metal oxide: titanium oxide (having an average particle diameter of 0.25μm)

Polymer compound: ETHOCEL (registered trademark) 100 cp (manufactured byThe Dow Chemical Company)

Solvent: terpineol

(Formation of Second Reflecting Layer)

With 1 part by mass of “ETHOCEL” (registered trademark) 100 cp as abinder resin, 90 parts by mass of a solvent (terpineol) was mixed, andthe resulting mixture was dissolved under heating at 80° C. to obtain aresin solution. To the resulting resin solution, 9 parts by mass oftitanium oxide was added, and the resulting mixture was kneaded toobtain a second reflecting layer paste.

This second reflecting layer paste was vacuum-printed on the barrier ribsubstrate having the first reflecting layer, inorganic protective layer,and organic protective layer formed thereon in Example 1. Then, theresulting product was dried at 90° C. for 1 hour to form a secondreflecting layer. A triple ion milling device EMTIC3X (manufactured byLeica Microsystems GmbH) was used to bare a cross section of the barrierrib. The cross section was photographed under a field emission typescanning electron microscope (FE-SEM) Merlin (manufactured by Carl ZeissAG). The thickness of the second reflecting layer on the side of thebarrier rib in the central portion in the height direction of thebarrier rib in the barrier rib substrate was measured and found to be 5μm.

Example 11

A barrier rib substrate was produced in the same manner as in Example 1except that the photomask was changed to a chromium mask havinggrid-like openings and having a pitch of 127 μm and a line width of 7μm. The barrier rib substrate was produced, and then, the reflectance,brightness, and amount of X-ray absorption were measured.

Comparative Example 1

(Formation of Barrier Rib Substrate)

(Preparation of Photosensitive Acrylic Resin)

A photosensitive acrylic resin was prepared using the following rawmaterials.

Photosensitive monomer M-1: trimethylolpropane triacrylate

Photosensitive monomer M-2: tetrapropylene glycol dimethacrylate

Photosensitive polymer: a product (weight-average molecular weight,43000; acid value, 100) obtained by addition reaction of 0.4 equivalentsof glycidyl methacrylate with a carboxyl group of a copolymer composedof methacrylic acid/methyl methacrylate/styrene at a mass ratio of40/40/30

Photo-radical polymerization initiator B:2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1 (manufacturedby BASF SE)

Polymerization inhibitor:1,6-hexanediol-bis[(3,5-di-t-butyl-4-hydroxyphenyl)propionate])

Ultraviolet-ray absorber solution: 0.3 mass % γ-butyrolactone solutionof Sudan IV (manufactured by Tokyo Ohka Kogyo Co., Ltd.)

Viscosity modifier: FLOWNON EC121 (manufactured by Kyoeisha ChemicalCo., Ltd.)

Solvent: γ-butyrolactone (manufactured by Fujifilm Wako Pure ChemicalCorporation)

In 38 parts by mass of the solvent, 4 parts by mass of thephotosensitive monomer M-1, 6 parts by mass of the photosensitivemonomer M-2, 24 parts by mass of the photosensitive polymer, 6 parts bymass of the photo-radical polymerization initiator B, 0.2 parts by massof the polymerization inhibitor, and 12.8 parts by mass of theultraviolet-ray absorber solution were dissolved under heating at atemperature of 80° C. to obtain a photosensitive acrylic resin solution.

A PI film, 125 mm×125 mm×0.05 mm, was used as a substrate. Thephotosensitive acrylic resin solution was applied to the surface of thesubstrate using a die coater so as to have a thickness of 100 μm afterbeing dried. The varnish was dried to obtain a coating film of thephotosensitive acrylic resin solution. Next, the coating film of thephotosensitive acrylic resin solution was exposed at a dose of 300mJ/cm² using a super high-pressure mercury lamp via a photomask(chromium mask having grid-like openings and having a pitch of 127 μmand a line width of 10 μm) the openings of which corresponded to adesired pattern. The coating film after exposure was developed in anaqueous solution of 0.5 mass % ethanol amine, and the unexposed portionswere removed to obtain a grid-like pattern. The resulting grid-likepattern was dried in the air at 150° C. for 30 minutes to form grid-likebarrier ribs. A cross section of the barrier rib was bared by cutting,and photographed using a scanning electron microscope S2400(manufactured by Hitachi, Ltd.). The height, bottom width, and top widthof the barrier rib and the distance between the barrier ribs weremeasured.

In the same manner as in Example 1, the resulting barrier rib substratewas used to form the first reflecting layer, inorganic protective layer,and organic protective layer, packed with a phosphor, and evaluated.

Comparative Example 2

A varnish was prepared in the same manner as in Example 1 except thatthe phenolic resin A was used instead of the polyimide A in Example 1.The barrier rib substrate was produced, and then, the reflectance,brightness, and amount of X-ray absorption were measured.

Comparative Example 3

A varnish was prepared in the same manner as in Example 1 except thatthe epoxy resin A was used instead of the polyimide A in Example 1. Inaddition, a barrier rib substrate was produced in the same manner as inExample 1 except that propylene glycol 1-monomethyl ether 2-acetate wasused instead of an aqueous potassium hydroxide solution to develop thecoating film in the barrier rib substrate forming step. The barrier ribsubstrate was produced, and then, the reflectance, brightness, andamount of X-ray absorption were measured.

Comparative Example 4

(Production of Glass Powder-Containing Paste)

To 50 parts by mass of the photosensitive acrylic resin produced inComparative Example 1, 50 parts by mass of the low-softening-point glasspowder was added, and then, the resulting mixture was kneaded in athree-roller kneader to obtain a glass powder-containing paste.

(Low-Softening-Point Glass Powder)

SiO₂, 27 mass %; B₂O₃, 31 mass %; ZnO, 6 mass %; Li₂O, 7 mass %; MgO, 2mass %; CaO, 2 mass %; BaO, 2 mass %; Al₂O₃, 23 mass %; refractive index(ng) 1.56; glass softening temperature, 588° C.; thermal expansioncoefficient, 70×10⁻⁷ (K⁻¹); average particle diameter, 2.3 μm.

A soda glass plate, 125 mm×125 mm×0.7 mm, was used as a substrate. Theglass powder-containing paste was applied to the surface of thesubstrate and dried using a die coater so as to have a thickness of 100μm after drying, thereby affording a coating film of the glasspowder-containing paste. Next, the coating film of the glasspowder-containing paste was exposed at a dose of 300 mJ/cm² using asuper high-pressure mercury lamp via a photomask (chromium mask havinggrid-like openings and having a pitch of 127 μm and a line width of 10μm) the openings of which corresponded to a desired pattern. The coatingfilm after exposure was developed in an aqueous solution of 0.5 mass %ethanol amine, and the unexposed portions were removed to obtain agrid-like pattern yet to be fired. The resulting grid-like pattern yetto be fired was fired in the air at 580° C. for 15 minutes to formgrid-like barrier ribs the main component of which was glass. A crosssection of the barrier rib was bared by cutting, and photographed usinga scanning electron microscope S2400 (manufactured by Hitachi, Ltd.).The height, bottom width, and top width of the barrier rib and thedistance between the barrier ribs were measured.

In the same manner as in Example 1, the resulting barrier rib substratewas used to form the first reflecting layer, inorganic protective layer,and organic protective layer, packed with a phosphor, and evaluated.

The evaluation results in Examples 1 to 11 and Comparative Examples 1 to4 are tabulated in Tables 1 and 2.

TABLE 1 Material for barrier rib Amount Compound (P) of epoxy End ofmolecular Phenolic Other raw reflecting Second Raw Materials chainhydroxyl group materials (*1) Curing agent layer Example 1 Polyimide ACarboxylic residue ◯ Epoxy compound A 100 Photo-acid generator A —Example 2 Polyamide A Carboxylic residue ◯ Epoxy compound A 100Photo-acid generator A — Example 3 Polyamideimide A Carboxylic residue ◯Epoxy compound A 100 Photo-acid generator A — Example 4 PolybenzoxazoleCarboxylic residue ◯ Epoxy compound A 100 Photo-acid generator A —precursor A Example 5 Polyimide A Carboxylic residue ◯ Epoxy compound B100 Photo-acid generator A — Example 6 Polyimide A Carboxylic residue ◯Epoxy compound C 100 Photo-acid generator A — Example 7 Polyimide ACarboxylic residue ◯ Epoxy compound A 100 Photo-acid generator B —Example 8 Polyimide B Amine residue ◯ Acryl compound A, — Photo-radical— Acryl compound B polymerization initiator A Example 9 Polyimide BAmine residue ◯ Epoxy compound A 100 Photo-acid generator A — Example 10Polyimide A Carboxylic residue ◯ Epoxy compound A 100 Photo-acidgenerator A ◯ Example 11 Polyimide A Carboxylic residue ◯ Epoxy compoundA 100 Photo-acid generator A — Comparative Photosensitive — — — —Photo-radical — Example 1 acrylic resin polymerization initiator BComparative Phenolic resin A — ◯ Epoxy compound A — Photo-acid generatorA — Example 2 Comparative Epoxy resin A — — Epoxy compound A —Photo-acid generator A — Example 3 Comparative Low-softening- — — — —Photo-radical — Example 4 point glass polymerization initiator B *1:theamount of the epoxy compound with respect to the compound (P) as 100parts by mass

TABLE 2 Amount of Arithmetic Amount structure Height Width L3 averageslope of derived L1 of of bottom Width L4 angle of the Ref- Bright-X-ray Mec- from epoxy barrier Pitch L2 of of barrier of top of L1/ L4/side of lectance ness absorption hanical compound (*2) rib barrier ribrib barrier rib L3 L3 barrier rib [%] [%] [%] strength Example 1 13 100127 10 10 10.0 1.0  2 125 120 115 A Example 2 13 100 127 18 18  5.6 1.0 4 115 110 107 A Example 3 13 100 127 15 15  6.7 1.0  3 120 115 110 AExample 4 13 100 127 12 12  8.3 1.0  3 122 117 112 A Example 5 13 100127 12 12  8.3 1.0  2 123 118 113 A Example 6 13 100 127 11 11  9.1 1.0 2 124 118 114 A Example 7 13 100 127 10 10 10.0 1.0  2 125 120 115 AExample 8 — 100 127 20 10  5.0 0.5  5 110 105 105 B Example 9 13 100 12712 12  8.3 1.0  5 112 108 110 A Example 10 13 100 127 10 10 10.0 1.0 —140 140 102 A Example 11 13 100 127  7  7 14.3 1.0  2 130 130 120 AComparative — 100 127 25 10  4.0 0.4 10 100 100 100 C Example 1Comparative — 100 127 16 14  6.3 0.9  7 105 102 102 B Example 2Comparative — 100 127 12 12  8.3 1.0  4 120 115 110 C Example 3Comparative — 100 127 30 10  3.3 0.3 20  95  95  90 A Example 4 *2:theamount of a structure derived from the epoxy compound with respect tothe compound (P) as 1 mol

In Examples 1 to 11 in which the barrier rib was constituted by amaterial containing the compound (P), the reflectance and the brightnesswere high. This is presumably because of the following: the barrier ribwas formed of a polyimide that was one of the compounds (P) and hadexcellent heat resistance, mechanical characteristics, and chemicalresistance; hence, less damage was caused by heating and the like in thesputtering step for forming a reflecting layer, and the smoothness ofthe surface of the barrier rib was not decreased by a solvent and heatin the phosphor packing step; and thus, a first reflecting layer havingexcellent smoothness was obtained. Furthermore, the sufficientmechanical strength conceivably inhibited the fracture and breakage ofthe barrier rib during the vacuum printing in the phosphor packing stepand the like.

In addition, it is conceivable that, in cases where the barrier ribcontained the compound (P) and a structure derived from an epoxycompound, the processability was better, the width of the bottom of thebarrier rib was made smaller than the width of the top of the barrierrib, and thus, the amount of the phosphor packed was increased,enhancing the brightness. It is conceivable that, particularly inExamples 1 to 7 and 10 to 11 in which an end of the molecular chain ofthe compound (P) was a carboxylic residue, the cationic polymerizationprogressed sufficiently, thus making it possible to form a barrier ribhaving excellent smoothness, and to further enhance the brightness.

On the other hand, in Comparative Example 1, the barrier rib was formedof an acrylic resin not containing the compound (P), and thus, thearithmetic average slope angle on the side of the barrier rib wasworsened, and the smoothness was decreased, thus decreasing thereflectance and the brightness. In addition, the chemical resistance waslower, and thus, the barrier rib in the phosphor packing step wasdeformed. In Comparative Example 2, the barrier rib was formed of aphenolic resin not containing the compound (P) but containing a phenolichydroxyl group, and thus, the arithmetic average slope angle on the sideof the barrier rib was worsened, and the smoothness was decreased, thusdecreasing the reflectance and the brightness. In Comparative Example 3,the barrier rib was formed of an epoxy resin not containing the compound(P), and thus, the reflectance and the brightness were suitable, but themechanical strength of the barrier rib was low, and the barrier rib wasfractured or broken in the step of producing a scintillator panel. InComparative Example 4, the barrier rib was formed of alow-softening-point glass, and thus, the glass powder melted generatedroughness on the side of the barrier rib, decreasing the smoothness ofthe barrier rib. In addition, the glass melted made the width of thebottom of the barrier rib larger, and accordingly decreased the amountof the phosphor packed, thus decreasing the amount of X-ray absorption.As a result of these, a decrease in the reflectance and the accompanyingdecrease in the brightness were observed.

DESCRIPTION OF REFERENCE SIGNS

-   -   1: Member for radiation detector    -   2: Scintillator panel    -   3: Output substrate    -   4: Substrate    -   5: Barrier Rib    -   6: Phosphor layer    -   7: Barrier membrane layer    -   8: Photoelectric conversion layer    -   9: Output layer    -   10: Substrate    -   11: First reflecting layer    -   12: Organic protective layer    -   13: Second reflecting layer    -   14: Phosphor    -   15: Binder resin    -   L1: Height of barrier rib    -   L2: Distance between adjacent barrier ribs    -   L2(X): Distance between adjacent barrier ribs in the X-axis        direction    -   L2(Y): Distance between adjacent barrier ribs in the Y-axis        direction    -   L3: Width of bottom of barrier rib    -   L4: Width of top of barrier rib

1. A scintillator panel comprising a substrate, a barrier rib formed onsaid substrate, and a scintillator layer having a phosphor and sectionedby said barrier rib, wherein said barrier rib contains one or morecompounds (P) selected from the group consisting of polyimides,polyamides, polyamideimides, and polybenzoxazoles.
 2. The scintillatorpanel according to claim 1, wherein an end of the molecular chain ofsaid compound (P) is a carboxylic residue.
 3. The scintillator panelaccording to claim 1, wherein said compound (P) has, in said molecularchain, a structure derived from a phenolic hydroxyl group.
 4. Thescintillator panel according to claim 1, wherein said barrier ribfurther comprises a structure derived from an epoxy compound.
 5. Thescintillator panel according to claim 4, wherein the amount of saidstructure derived from an epoxy compound corresponds to 3 mol or moreand 25 mol or less when the amount of the compound (P) is 1 mol.
 6. Thescintillator panel according to claim 1, comprising a metal-containingreflecting layer on the surface of said barrier rib.
 7. The scintillatorpanel according to claim 6, comprising a protective layer on the surfaceof said reflecting layer.
 8. The scintillator panel according to claim7, comprising a second reflecting layer on the surface of saidprotective layer.
 9. The scintillator panel according to claim 1,wherein the aspect ratio (L1/L3) of the height L1 of said barrier rib tothe bottom width L3 of said barrier rib is 5.0 or more, and wherein theratio (L4/L3) of the top width L4 of said barrier rib to said bottomwidth L3 is 0.5 or more.
 10. A method of producing a scintillator panel,comprising: a barrier rib forming step of forming a barrier rib on asubstrate to define cells; a reflecting layer forming step of forming ametal reflecting layer on the surface of said barrier rib; a packingstep of packing a phosphor in the cells defined by said barrier rib;wherein said barrier rib contains one or more compounds (P) selectedfrom the group consisting of polyimides, polyamides, polyamideimides,and polybenzoxazoles and a structure derived from an epoxy compound.